I'm paying substantially (25%) less than that for use of a syndicate PA28-161, last year I took it to the Hebrides and back for a week. Here at EGHP international, there are usually loads of shares going in various 2 and 4-seaters for a few thousand and much less than £68/hr running costs (plus monthly), you just need to make sure you're joining a syndicate whose rules don't mind you taking it away for a week once in a while.
How big are you and your wife? I'm not sure I'd manage getting Mrs.G and I in a C152 + a weeks worth of bags + enough fuel for the longer legs on that sort of trip - that's why I fly a Warrior! Taking "BW" to the Hebrides and back, Mrs.G, I, reasonable - but not excessive bags and clothes, and full (180 litre) tanks were just shy of MTOW. Full tanks are particularly necessary 'cos fuel can be less available up there than you are used to down here.
G