There is one of those Derbi's for sale in Fowlers in Bristol. Was looking at it a few weeks ago. I've ridden a few other standard bikes with the 660 motor and I'm amazed how slow and bunged up they feel compared to mine with the after market exhaust and filter.
I stripped the bike more this evening. The more I strip it the more I can see the bike I'm trying to find. Its there its just hidden by loads of usless metal and plastics. I will make the final call this weekend once I've had time to strip it of everything I don't need. I can see a few problems but hey that's part of the fun.........
**** it, I'm cutting it Friday evening. In for a penny in for a pound :-o