PJ,
Can't comment on JAR/FAA differences, but I think you will be pushed to find a reasonably paid job in the UK with low hours. There are a few charter companies that use pilots on an ad hoc basis but they pay by the flying hour or day, whichever is the lower in most cases. Also, most commercial operators use turbine aircraft so that may be be the way to go.
Hope this helps.
Cheers,
NEO.
