I have seen people including LAEs leaving companies for years and if that company does not pay at least a similar amount to its neighbours they will continue to move. The last small company I was in danger of losing several major types as senior LAEs left apparently for no reason...until the last one said it was about poor pay which hadn't been reviewed for three years. (the company owner was quite happy with that). I remember in the mid/late 80s that there was a huge Heathrow/Gatwick pay battle where LAEs swapped almost regularly between Virgin and BA (some possibly still do).
When I got to Norwich the local helicopter companies pay was better than fixed wing pay - and with better bonuses too! As a type rated LAE, I left Norwich for a 45% pay rise for half of the job I previously did. Unlike most pilots, most engineers are not Union members (I was) and their pay rates can be very personal and any large company pay scales are not often publicised. (KLMuk applies 'Norwich Weighting' to its pay - similar to London Weighting but is set at minus 30%). Having said all that, my wide scope of experiences at AirUK / KLMuk set me on my feet for civil aircraft management and certification....and although I'm recently retitred, I'm still looking for short contracts!