Is NHS orthognathic surgery as a 21 year old possible?

I’m 21 and I had braces put in when I was 14 but obviously, this never addressed my recessed jawline. I would say that I’ve experienced sleep apnea more than once, I have extremely bad hay fever allergies (which caused my nose to be blocked) meaning I would often be mouth breathing and the lower half of my face is asymmetric (nose, lips, jaw). I booked in a GP appointment for next week to discuss my jaw and breathing issues and given some research, I think I would be a candidate for Orthognathic surgery. I was thinking that I may privately seek out a CBCT scan and a written report to speed up the process for a maxillofacial referral but I’m not sure if it’s necessary. What do you think I could expect from the GP appointment if I don’t get the scan or written report?