Ok I might be able to help as I did a orthotics and prosthetics rotation when I was in training many years ago.
I have a few good friends who are orthotists and I still use the orthotic workshops when I am working nearby in my NHS clinic and I. need to adapt equipment quickly.
To be fair from what I can see, things in the NHS service have not really moved on much in the last 20 + years in terms of what is provided from GP referral. There are long waiting lists too.
I work in another highly specialised field and am now a private contractor for the NHS.
If you are looking for very high tech materials and orthotic assessment processes in the North of the UK, these chaps might be what you are looking for.
https://www.crispinorthotics.com
I have no connection to the company, but looking at what they offer, they seem to be what you are looking for.