In reply to craig1983: Hi Craig
It sounds like your boots are a tad small - my guide for fit is that if I can't cant my fingers behind my heel without raming my toes against the end then there too small.
I recently sold some SL M3's on UKC for £65ish from memory, I only wore them a couple of times and they we're not for me. You may get a bit more on ebay.
I wear la sportiva tango extremes for summer alps and scottish winter climbing and the SL's have a fairly stiff sole in comparison - my feet are only 41.5 though!
You could try scarpa mantas which are b2 are ok for munros in winter plus grade III climbing.
Best bet is try a few pairs on and see what fits, you could then try and buy second hand to save some cash?
HTH Davey