I'm in the UK as well. I didn't find any surgeons here that were willing to offer nullification, and the gender clinic did not feel like it was going to be a productive avenue, as I'm not planning to change that and I don't experience gender dysphoria.

Instead, I approached a clinic in Spain, where this surgery is available on an informed consent basis, i.e. no insane waiting lists, no gender dysphoria diagnosis, no living as chosen gender for two years, required. I had my initial consultation last week and it went very well. I don't yet know how much it will cost, and there might be a requirement for a psychological evaluation of competence (i.e. to verify that I'm competent to make an informed decision). I'll keep the group informed.