Impossible to say what the CAA would do. In the run-up to EU Regulation they seem to have thrown LASORS away and are making things up as they go along. However, I doubt that they would accept your next LPC/OPC as it would, by definition, be for revalidation of a P2 rating. Even if they do accept the OAA training, I would expect them to insist on an LST as PIC, conducted by a JAA TRE.
The only way you can get a definitive answer is to contact the policy geeks at Gatwick, if you've got a day or two to spare - their service standards seem to have been thrown out with everything else. Their e-mail is
[email protected]