Q8 Pilot,
I assume you want to do your A320 rating at a uK TRTO, otherwise whats the point in transferring your Licence to a UK JAR?
You don't need a current IR to do a second MPA rating like the A320, Lasors refers to initial issue and 1st MPA type.
Curious going from 777 to A320, Chalk and cheese, and with 1500 hrs 777 jobs a plenty, not so much nil hrs A320.
Ant TRTO worth their salt will tell you what you need to do.