Friends of mine who worked for JAL at LHR lived in Dublin, Manchester and Paris - used to have them on my flights often. Obviously when on standby you would have to be within 45 mins of LHR, crew then stay in a b and b or at friends. Officially i think they gave the airline a UK address but just went home on days off. No real difference to going away on a break when on days off is it? I used to commute from Teesside when on both longhaul and shorthaul and had no problems.