No offence taken Doc.
Back to the original topic.
The only airlines that have hangars at LHR as you probably know are BA and Midland.
I know that both companies go back through previous applications to offer job vacancies unless the vacancy is one that is specialist.
Rumour has it that Virgin have a hangar in the pipeline and I am sure that they will have to advertise externally to fill it.
The line jobs are BA,Midland and Virgin as the major employers. It seems that every other airline uses LHR as an outstation with no real maintenance being carried out. If you drive around at 3 in the morning it's only these 3 airlines engineers punting.
Cathay Pacific have quite a large operation with their daystop a/c being worked in the Midland hangar, mostly by Midland staff, with certs by their own staff.
I think that in any working envioronment word of mouth/recomendations seems to be the norm.