I think your only option to get any credit would be:
- do your CAA ATPL exams
- Do a type rating on a MP aircraft (hopefully one you already fly in the military (eg Voyager/A330) which would get you your ATPL
- Do an EASA licence conversion on the basis of your CAA ATPL (so again straight to the exams)
- Do another LST on the type (this time for EASA), obtain ATPL licence.
speak to "UK Flying". They know the drill