In reply to siobhan66:
I've used a Theracane, in combination with shoe-stretching liquid, to good effect to stretch out specific pressure points in leather shoes on the top toe knuckles. The Theracane is a plastic device shaped like a shephard's crook and is intended for self-massage. But the ball at the end of the crook is a good shape for stretching, and the cane configuration gives you a lot of leverage for pressing on a point to be stretched.
If the upper is synthetic and/or the fit problem is not one of specific pressure points, I don't think my experience will be of much use.
It may no longer be true, but there was a time when Evolv would sell you two different-sized shoes. The price was more than the regular price for a pair, but not double the pair price either. Probably the best choice is custom climbing shoes. There is a place in the US ( Kn Climbing,
https://knclimbing.com/ ) that does it, but there are currently updating their sizing process and aren't taking orders. Perhaps there are UK or European cobblers who also do this kind of work?
Post edited at 16:48