For what it's worth, Telefónica is notorious for doing LOTS of testing different ways of throttling, caching, blocking, accelerating etc... (and not being that "great" at it)
The general INTENT is not "omg, they want to block me from doing things!!!", but rather they are trying to save/optimize on bandwidth. As far as I know, they have at times been known to block SOME traffic they consider "voice" as it comes in conflict with their main business line, but mostly this has been tried and then stopped as it generated more headaches than cash.
With all the caching/accelerating, etc, a LOT of times they mess up with ICMP packs which handle testing MTU, in conjunction with changing the actual MTU of the links, the result of this is that your kit sends larger blocks than the links can handle and then they get mashed/munged during fragmentation/reassembly. And the consequence of that is that a lot of "real" packets don't get through (often the ones on or around the *perceived* MTU limit), so your data then behaves as if it was working on a VERY lossy link (imagine around 40%+ packet loss...). You won't see problems with a regular ping, but you may if you check with ping sizes around the MTU limit.
At other times, as Telefónica is trying to optimize using DPI (deep packet inspection) to check what protocol is being used, they may not correctly recognize your traffic and thus munge it in someway. Effectively acting as a throttle, but not because they actually "want" to throttle.
What can you do about it? Not much, because all of this is handled by the inner sanctum of the tech-priests and they don't communicate with mere mortals such as tech support of commercial reps, there's no way to get through...
With a regular residential grade link, the attitude from Telefonica is "take it or leave it as-is, we don't care, this is what we give". In general they are valid for the purpose, but if you want business grade quality AND the possibility of complaining (and being heard), you need to get a business grade link (ie ditch Speedy and get info-internet at 5x the price with 1/4 the speed).
It's nice to WANT to notch it up to "they are throttling me" or "NSA is spying on me" and any other conspiracy theory, but once you mention Telefonica it's more a case of "Do not attribute to malice that which can be explained by incompetence".
(and yes, NSA is probably spying on you ANYWAY...).
The above come from a lot of experience with different telco's, a lot of contact with people inside telefonica and seeing how telefonica operates in quite a few countries (including Spain and Peru). Just take it as face value, I'm not trying to prove a point. If it helps great... if not, well, good luck with other venues...
My $0.02

What exactly are you trying to achieve?
Some scenarios:
A) remote to central with 2 ISP's at remote with "cheap regular" DSL type connection going to central where there is a "big fat pipe" (multihomed?)
A.1) a one of for a single remote .2) something repeatable for multiple remotes
B) remote to central with 2 ISP's as A) and with (same?) 2 ISP's at central (also B.1 & B.2) as above).

Do we have any fixed public IP addresses anywhere in the equation (or is this out of budget too)?
In all cases in which direction is the data flowing mainly?
Also, what is the purpose mainly here? Getting higher speed? Higher redundancy? Less latency (hah!) ?
> The hardware solutions I've found are expensive for a small business
Can you define expensive, what type of price is out of it (both for hardware and for links)?

I would GUESS that the end result needed is to connect LAN-1 to LAN-2 , so it doesn't HAVE to "look" as a single channel for the routers involved, just that the paths
aggregate and are redundant... But a bit more information would be appreciated!

All the East coast of Africa has up to now been severeley lacking in possibilities of connectivity, and has had to make do with satellite links which are high latency and expensive (a DEDICATED satlink of 1Mb up and 1Mb down is in the ballpark range of around $10,000 per month, yes ten-THOUSAND per MONTH).
The West coast has had the SAT-3 cable for a while (2001), with a total capacity of 120Gbit/s (according to Wikipedia). Most of that lands and gets used up in SouthAfrica and in Nigeria. South Africa is in a decent situation because they have a country-wide distribution network that lets them hand off the network to most places. In Nigeria, however, try getting a connection on the SAT-3 outside of Lagos...
The problem throughout Africa is not only that of lack of backbone country-to-internet connectivity, but actually that of a decent distribution network within the country itself.
It's of little use to land a multi-gig cable at a certain place if then you don't have the infrastructure to re-distribute it. Maybe a chicken and egg situation... No backbone, so no point in building local distribution. No local distribution, so no point in building a backbone...
Nigeria is arguably the 2nd most developed country in Africa (After S.A.), and if you want a link outside of Lagos, your best bet is to go for a satlink. In fact, even INSIDE of Lagos, ISP's use sat-link bandwidth because of the instabilities of using Nitel to get to the SAT-3 landing station. So, if the 2nd most developed country has had a sub-link for 8 yrs and can't get the signal distributed, how long do you think it's going to take for this new cable to actually start making waves?
I'm betting it's mainly going to be used in the short term for South Africa (will drop prices for them!), and for the rest of the countries will serve to carry voice from the main hubs of the cellphone operators...
So to give an idea of how things happen in lesser developed countries:
-In Congo Democratic Republic, cellphone coverage is getting to be quite extensive (at least in the population centers), but if you make a phone call from Goma (eastern border) to the capital Kinshassa, your call goes over a satlink (no city to city connection). Even worse, if you call a friend/colleague also in Goma, but who happens to use a different operator, your call may actually make TWO hops: first sat-hop back to Kinshassa, then handed from one operator to the other, and then back over another sat-hop to Goma...
Think about it.

There is no automatic "yeah this is great" or "nah, this is crap" answer. All those advising one way or another directly are jumping the gun like crazy.
Your big question 'should I stay or should I go now?' only has one answer: 'it depends'.
I've been in similar situations before and in some cases taken shares, in others preferred to take more wages, in others left.
From what you state, the company is "a small IT consulting firm" and you are "a key resource". I think the important information that you're telling us is that the company is SMALL (5-10 people tops?) and that you are one of the key guys.
If taking 10% is equivalent to now considering you as a partner with a say, then now you have "clout" and will be regarded maybe in a different way.
Obviously you want to place a "value" on these shares. Does the company make a profit each year that they turn around and share with the partners? If so, how much has that been... If instead, all they do is adjust top salaries to what company makes (as happens with a lot of companies), then no dividends are paid out. In this case, does your also get adjuested? At what level? If you are made an equal partner on consideration (even if not on shares), will your salary now be on equal par to the others?. Being a "small company" probably means that it will stay privately owned, and never be sold, as such, your 10% probably won't ever have a decent "sale" value, so that part will not be worth much (if anything), unless the company has a declared monetary value, and thus the 10% can actually be redeemed for something... but for that you'd want guarantees in writing that it would be possible to sell at some point in the future.
A downside to "being a partner" is also that often now your guarantee of salary goes to the pits. I'll explain. As a "grunt" worker, you expect your salary as the company isn't yours. The owners generally (if they care at all about their employees), will first pay employee salaries before paying themselves. As an "owner", if hard times hit, you may find yourself with a salary that although on paper your still getting it, in reality you get what is left over... (anything missing considered to be "owed" to you by company, to be paid when [if?] things improve... after all, it "doesn't matter as it's your company after all!!!"].
You also mention that "I was ready to quit for consulting". So, you want to quit this small consulting company and go set up one yourself of your own? Well, if you are one of the key resources, maybe you are better off with your own company than having 10% of one shared with another 90%...
As mentioned above, it all depends... Conditions being special to your particular company, what the outlook is, what consideration you get for your shares, how that affects salary, if the value of shares is actually tangible down the road, etc. Impossible to tell without knowing more, but at least those are the things you should be factoring in to see if you want it or not.
Oh, and of course, the first question of all "are you comfortable with the company?" If not, then your choice is clear in any case.
$0.02