Aerads
LHR is a 'temporary' base - so you will be allocated one of the others and seconded. Huge bunfight for southerners to get down there so I wouldn't hold your breath for it!
Pigeon obviously enjoys working there (it is a good company), but in the last 2 years weekends have all but disappeared from home life - either down at LHR for the friday night emb migration or covering the rest of the work at home while everyone else heads to LHR.