Canada Goose,
Check this out in the way I suggested. Your AME is wrong. I'm not surprised; I had mine insisting a few months ago that students were passengers and as an instructor I needed a medical every six months. He even phoned some idiot at the CAA who didn't know their own rules, who confirmed it! I sent him a copy of the document I mentioned in my last post - has he had the courtesy to thank me...not on your life. AMEs are doctors who by definition think they're God. If you do a search you'll find a thread from last February or thereabouts when I asked about this, and various people were saying the AMEs needed better information from the CAA, and they do. I just don't trust mine to know this stuff any more; I'm the pilot, I'll find out about aviation law and inform HIM!!!!!!! And I suggest you do the same.
As for not letting it expire, a load of crap! I got a Class 1 before I did my CPL, then let it lapse, then got one again before I got my FI rating - no problem at all. AMEs hate you doing this as it messes up all the nice regular dates of tests for them. Well, just offer to do the really, really simple mental arithmatic for him; it's not a big deal.
As you may have gathered, I am totally pissed off with AMEs; they don't know about all this stuff - and they should!!!!!!!!!!!!!!
I notice you live in Shropshire. Do you see an AME in Cheshire by any chance? PM me about this if you like.