In reply to paul walters:
I’d be very keen to see your boots and feet back at Up and Under. We pride ourselves on our boot fitting services and specifically use staff who are experienced winter climbers and Alpine mountaineers as well as trained boot fitters to help when anyone is trying mountain boots on.
Whilst I cannot really comment without having your boots and feet in front of me I would be a little concerned that if you are getting heal movement in a size 45 that you are recommended to jump to a 46.
The comments from Stephen Reid (he certainly knows what he’s talking about), Grendel and Mountain Llama regarding rules of thumb for fits is spot on and I’d be happy for you to try a 45.5 to compare, but I would anticipate that if you are having problems with heal movement that that won’t necessarily be the best solution.
It could be that trying an alternative lacing method or sock combination is all that you need to achieve perfection. Different foot-beds or heal inserts (if necessary) may also help. Were you wearing the sock combination at Cotswold Outdoors and during your try on time at home that you chose / we recommended on your visit to Up and Under?
We are always keen to help solve boot issues for anyone whether they bought from us or from competitors as comfy feet are as important as it gets when you are out in the hills.