In reply to paul wood:
I tend to agree, it happens in guidebooks too. The new North Wales bouldering guide has new first ascentionists listed for boulder starts of routes that were first climbed in the 80/90s.
I think sometimes on ukc it depends on the discretion of the crag moderator, for example I don't approve a fair amount of "new route" requests for Bwlch Y Moch, because most are either already existing routes, are a combination of existing routes or tiny variations.