Hi and welcome,
Contrary to what the others have said, it appears we do now have Wing (~county level) and Region level Medical Support Officer roles. The role seems to have snuck in under the radar, and appeared in our internal IT systems within the last couple months. How this role works alongside the First Aid Training Officers is not yet known to me currently.
It has certainly been done in the past locally where an individual with skills useful to the organisation has been recruited with the intention of joining as a subject matter expert. Initially you might join a local squadron, but you can quickly move into that higher level role once established.
I believe our electronic ‘Join’ process hasn’t been designed to account for individuals directly joining a wing or region so you may need to sign up to a sqn first.
I’d reach out to your local Wing Headquarters listed here and go from there:
Contact us | Royal Air Force Air Cadets (mod.uk)