Interesting guys - thanks.
The engine in question is a Hewland AE75., and I'm currently doing c.100hrs/yr - although I would expect that to rise slightly if I buy the 'plane in question.
Trouble is, it seems the expert engineer for these beasts has a bit of a vested interest (I'm not implying anything dodgy here) as he has a virtual monopoly on the maintenance front. Hard to get a truly independent view.