Hi, I've been doing some restriction hunting based on the pointers you gave me, I have had some luck...
1. Found a throttle limit screw - Stamped on it many times (while cursing) , launched it towards the bin !
2. Removed Carb Inlet Boots - look to be massively restricting as the inlet in the head is much bigger than the hole in the boot see link for pics on flickr
https://www.flickr.com/photos/144645758@N07
3. Found some boots on ebay with no restricting tiny holes
4. Had a cup of tea and became smug ?
This is the part where you tell me the bike will explode, burst into flames and destroy the whole of Oxfordshire, If I attempt to fit the new boots?