Will they be bringing Johnny Marr in to calibrate it?

Not completely correct, but on the right lines...

GSM and 3G phones listen to the cell tower's Pilot carrier, which contains a whole bunch of data (which network, neighbouring cells etc). thenetwork will broadcast a request for a particular phone to contact it when there is incoming traffic (eg call or SMS) for that phone.

To reduce the volume of traffic, it only broadcasts this request over a small(ish) no of cells, called a Location Area (LA). And how does it know which LA to poll - because part of the broadcast data on the pilot channel is the LA identifier - so when a phone switches from listening on one cell to listening on another (which it doesn't inform the network about unless it is mid call) it checks the LA number, and then updates the network with it's new LA when the LA identification changes.

So if anyone on the plane left their mobile switched on (and with a couple of hundred people on the plane this is a racing certainty), then by checking the operater records for all the phones, LA updates will be there (and yes, operators are required to keep this meta-data for the intelligence services).

In consequence, I would be extremely surprised if the NSA / GCHQ / KGB and Chinese Military Intelligence did not already have a good indication off where the plane was (or was not).

Probate is a standard part of English Law

This is exactly correct.

As executor of a will you have to get probate, which means that a court has to confirm that
1. The will is valid
2. You are appointed as executor of the estate by the will
3. You are a fit and proper person to be appointed as an executor (eg no convictions for fraud, etc)

This is (in most cases) a rubber stamp - you send off the documents, and an official letter (the Grant of Probate) comes back from the court a few weeeks later.

Until you have this, you have no legal standing. Once you have this, you have the right to dispose of the estate as per the will. Any organisation will ask to see the Grant of Probate, and will refuse to deal with you until you have this.

This sounds very like the existing 3G soft handover feature.

I'm not involved in that area of telecoms these days, but I do recall that the network equipment manufacturers were finding it very difficult to get working, and requiring some serious compute power.