I went through Air-COSPers-Disclosures which if you add an @mod.gov.uk to this, you should get through. You'll need (I quote):-details of information you require (eg. Full service records or full service and medical records)
-Service Number
-Approximate dates of Service
-Full postal address
-Proof of Identity, please note we now require proof of both name and address. A driving licence can be used to prove both name and address. If you choose to send a passport we will also require a utility bill as proof of your address.