In the end stripped both calipers, cleaned the pistons with brake cleaner & re-greased with copperease.I think that they were a bit on the sticky side, but not all that much really.If there is a fault, it`s maybe just that the m/c is not very powerful, to the point of struggling to push the pistons out from the fully back position.
Cleaned & lubed they both bled up to a good brake in 15 minutes, so ta for the reply`s & another happy bunny that can get back out on his bike :-?. Thanks again Kev