If you pm Coax-on or Gunner REMF they should be able to tell you the info you require. Shall we say they are in the know about such things!
I knew there was a Sqn forming in Cornwall, but I thought it was going to based out of Truro. Could be wrong?
I think you're right about the Plymouth Sqn, I seem to remember the conversation about the need to have 383 Pet Troop based there if there's going to be a Tpt Regt in same location?
All the best.