Is it a once off or will you be going often? I go there with work and we have membership of the Royal Commonwealth Society (about 150GBP pa), not sure if you need to be British which I'm not, or associated with a British company or if indeed there are any restrictions, possibly not as they accept membership worldwide. (Mine was set up by work) Anyway they have a hotel and aparthotel just up the road from Trafalgar Square, and it's an easy trip from Heathrow. Aparthotels are kitted out with little kitchen, cd player, so it's great. More details here.. [broken link removed]