To answer the original question, albeit from many years ago, offshore North Sea salaries are approximately: new First Officer £40k, year 3 Senior First Officer £55k and year 10 Captain £85k.
Add to this a roster of equal time, or nearly equal days on and off duty, plus sleeping in your own bed most nights (unless working at a 'satellite' base) and you can understand why there are piles of hopeful application forms.
How long all this will continue is a moot point, but the vast majority of offshore pilots maintain their membership subscriptions to BALPA in the hope of prolonging this situation. Madness not to!