Tag Heuer repair ?

[langy]

One of the push buttons on my Tag Heuer 6000 chronograph has decided to part company with the rest of the watch, last time this happened it ended up having the movement replaced at a cost of £500 as water got in.

Trying to prevent a similar bill, so can anyone recomend a repairer (except LVMH) who could do the work.

TIA,