Sounds like great fun Peter, a really special time in our shooting past, I wish I had been there ... Yep the trigger plunger is L1 length in the L2A1. I have a few in my spares kit, including two that are about 6mm shorter, so I guess L2A1 examples.

I have Hythe sights in both my L1's, they really do help tighten up the groups don't they.