thanks for your input , much appreciated .... and very good advise .
i do not really plan on useing it in pre65 so not too fussy ,.
i just want forks with better performance than the standard c15 forks .
i have dwelled on the problem a little more , in my opinion , i may be wrong ? the only thing stopping me fitting for example- x l -fork legs in the original c15 top yoke is the absence of the pinch bolts
most modern bikes have pinch bolts on the top and bottom yokes , the british c15 have pinch bolts only on the bottom yoke and the top yoke takes large nuts which screw in to the top of the fork legs and tighten ,to secure legs to top yoke .
i do not think it would be a problem to ream out the yokes to take larger diameter fork legs , the problem is the absence of pinch bolts on the top yoke ?
if there is a way round this i do not know .