tom parry - As far as one can tell from the photo it looks like JV in which case it could be John Vasey or John Visick. John Vasey is quite a prolific potter, still at it in St Agnes (Cornwall) and sometimes hard to identify because he is versatile and his output is varied. John Visick's mark is very hard to tell from Vasey's but he was active for a much shorter period in the 1970s (at Carnon Downs, near Truro, Cornwall). I am guessing this is his on the basis of the clay body.
Phil - Hi Tom, Thanks for your reply. I wondered about John Vasey but couldn't find anything typical to compare it too. I live in Cornwall, so both make sense.
mark from silsden - sure it is John Vasey as I had a vase with this mark
Phil - Thanks Mark