In reply to tnj:
There may be other shops but, Lockwards seemed to be the only place in the country with a variety of liners to try out.
Mrs MooseMouse has an extremely wide forefoot(112mm in a size 4, think of the mythical hairy forest monster for an idea of the size!) and small heels and has struggled with several pairs of touring boots.
Lockwards had a variety of aftermarket liners and fitted a pair that has eliminated her problems.
I phoned just about every other shop, and we already had tried several in Chamonix. Most shops either just would not go near her feet or did not have many types of liner in stock, with only a vague notion of when they could get them in. Most were even very reluctant to sell her a new pair of boots!
The chap in Lockwards was a hero she was in the shop pacing up and down for about 2 hours getting it right.
Ellis Brigham in Aviemore also put a great deal of effort into shaping custom footbeds for her and the lass there seemed very knowledgeable and really into feet!
If your heading in that direction soon, I and several friends have had very good boot modifying service from the sport tech shop in Argientiere as well.
http://www.sportech-argentiere.fr/en/ski-shop-sportech.html
I tried various liners in Denalis that were one(maybe 1.5x) size too big and they just could not control my foot movement, especially when descending on foot.
The end result was lost toe nails and a year of buying new shoes as my toes were too bruised to wear my usual size!
It would have been cheaper to smash the front out of the big boots with a rock before the damage got too bad and then bought new boots!