After speaking to my neighbour who is a rolls royce engineer he seems to think the problem is one of the Crank/Camshaft sensors, Does anyone have any advice on replacing etc as there seems to be very little info available

thanks

They don't have crankshaft sensors.

All you have is some coil pickups, there are two of these that send a spark signal to the ignition box which then fires the coils.

If you don't have a spark then these may have failed.

If all your plugs are sparking it is ok to assume that these are ok.

There are no other sensors, only neutral / clutch switch and kill switch, the kill switch will cause no spark.

Does the neutral light come on? If so then it should crank over.

It sounds like you have fuel / carb / electrical related issues rather than a single component being at fault.

Especially considering you had the bike running on three...

In your first post you mentioned this ..

The only other thing i have noticed is that there are 3 clamps missing from the rubber intakes into the chambers there fastened to the carb but not the block !!

I'd get that sorted first, maybe that will help..

yep.. air-leak will help make it start difficult.

Where are you locateD?