I agree, all of the above options maybe helpful. Also, a good shop can stretch/flare the cuff of the boot. This may be helpful in combination with a heel lift (as noted above) to get the leg up higher and get the cuff around a narrower part of the leg. If none of this works, some boots have wider cuffs available, but by the time you go through all this (and you say the fit in the foot is "OK"--seemingly not great) it may be better to consider a new boot. Hope this helps.