Why are you only thinking about a military flying career now?
Why didn't you join the CCF at university?
You didn't join the Combined Cadet Force as this is an equivalent to the Army, Air Cadets or Sea Cadets but is usually only found at public school.
At the university the RAF has a number of UAS University Air Squadrons. Your confusion suggests an escape route. There are only a few UAS, East Midland, Lancs, etc, I don't know the names but they are only near some universities. The One at Southport is 'near' (relative term) Liverpool, Manchester, Salford and Lancaster and any othe rodds and sod in that area.
If they did not have a high profile, or even presence, at your uni then that is your 'out'.
The important answer is to the question 'What have you done to further your knowledge of ...'
We had a MOST impressive woman from Barclay's Bank. She decided she wanted to be an RAF Fighter Controller. She asked their airships (directly) for visits to RAF Waddington and the E3 and to the School of Fighter Control to see if the jobs were suitable for her, never mind whether we wanted her. She was formidable and left with a tag 'must recruit her.' Unfortunately I do not know if she applied nor how the recruiters and trainers handled her (if they did).
Finally, while it is true that the RAF streams its pilots to match abilities and bums on seats, an overriding and absolute desire to do just one thing, such as SAR or Merlin cabs, is usually enough to influence those that will select your posting.
A nav in the 70's had a burning ambition to fly SAR Sea King. He was bloody good but posted to Nimrods. After a tour and the introduction of Sea Kings he applied for and passed the aptitude tests to be a helicopter winch operator and nav. He then served 20 years on the SAR Force.
In my case I wanted to navigate rather than pilot. I too got what I wanted.