Just a thought....
I notice that there are queries as to what to do with the ID disc once the stone has been re erected...
I've had a couple of ideas thus far...
Is there a chance - via the stonemasons - the disc can be inset somehow into the headstone? This way he is not just an anonymous headstone but a remembered soldier with his service for all to see...
Or perhaps on a small plaque within St Peters itself with an "In Memoriam" inscription?