If the landlord will allow a dish install, they're reasonably priced (£25pcm for all channels, excluding movies and sports), and can also provide your landline + broadband/fibre. We pay ~£70pcm for Sky, Movies, landline, and 40mb fibre (which has no download caps or traffic shaping).
Alternatively, you can pull out all the indoor Virgin Media cables (assuming they've haphazardly tacked them to the skirting boards) to the outside of the property (where they should be joined with a threaded 'F' barrel coupler), and they'll have to run them to where you want them during the install. However, their TV packages are somewhat confusing, generally more expensive than the Sky equivalent, and they'll charge more for the subscription if you don't take a phoneline as part of the deal.
Failing that, buy a 20m aerial extension kit and a Freeview HD box from Amazon, and pray that you get a good signal.