Roy
Have a gander at
The Commercial Diving Directory
This is a professional divers website run by a longtime SAT diver/superintendent and has a worldwide following. Questions such as yours are regularly received and commented upon by guys who have been diving since the early North Sea days. Be prepared for some sound truths -
it is a hard game to break into. Most guys start off shellfish diving and then progress to fish farm and civils work (piss poor pay and conditions). To get offshore these days usually means the Middle East - again diabolical pay and conditions but guys put up with to get work experience and the log book filled up.
Cheers
Bernard