Rouge and DJL,
Thanks for the replies. I think I will, as you suggest, pop along to RIBEX and visit the nice propellor people and try some bigger pitch props. The rev limiter doesnt seem to kick in, mainly because I don't want to let the engine rev much past 6000rpm.
Thanks very much guys for your suggestions,
Edit: I am in Portsmouth
DJL: Thanks for your kind offer, but I am reluctant to try much before the engine is fully run in hence the general enquiry. I think RIBEX, as you suggest, is the best time to have a fiddle!