No, an SEP Class Rating revalidation LPC has a specific content and must be flown with a CAA-authorised Flight Examiner.
However, if all that is required is completion of the 'dual training flight' element of revalidation by experience, then a FAT may count. I secured a policy agreement from the CAA on 7 Aug 2001 as follows:
I refer to your letter dated 14 July 2001 and our conversation last week regarding the dual instructional flight required for SEP Class Rating revalidation.
I can confirm that any instructional flight or check flight conducted by a military instructor/examiner where required during the course of a pilot's service duties will satisfy the dual flight with an instructor requirement. This will include military IR check flights.
Flights conducted by a military QFI but not required as part of service duties will not be acceptable for this purpose.
The EFT FHT in lieu of a PPL Skill Test is an initial issue credit only; thereafter you have to meet the same revalidation requirement as anyone else.
What is/was the expiry date of your SEP Class Rating?