where's your Visa for????
US visa required for long haul. Yellow fever jab req too, for africa etc.
(which) aricarft types that you are trained for on lhr-euro?
Main fleet is Airbus 319/20, 757, and 767. Unlikely, though possible, that you'll get 737 instead of 767.
wots the best trips goin from lhr?
Depends what you like. MAD/LCA/BCN/LYS. FCO is always good, best food/shopping/culture/people. ARN was good until moved hotel. Some trips earn more money, some better culture etc. The best trips are the ones with the best crews. Doesn't matter where you are then. 767 covers occasional Worldwide shortages, NAS/DAR/EBB/ACC/TLV and QRS(standby).