Graham,
The best guy to ask is Bill Pye, he knows Fantic through and through - best place to get parts for Fantic bikes in the UK. If you live near the North East of England, the address is
Frankfield Garage
Great Ayton
Middlesbrough
North Yorks
TS9 6BZ
Give him a call on 01642 722378 - he will help you out.
Stuart