A and C
There are many ways such service can be formally recognised. There are Commendations from Commandant Air Cadets, AOC 22 Group and CAS; above those there is the DCLA - Defence Council Letter of Appreciation.
An MBE or the more recently re-introduced BEM may be a player but - with all due deference to the subject - they require more than Long Service and Good Conduct as competition for State Awards such as these is fierce.
Best move is to discuss it with the OC Wing or (probably better!) the Wg Ex O. If you don't know who these are, PM me with details of location or Sqn and I can provide a contact.
Teeters