Afternoon Keith,
I cant promise to solve your query as you don’t say how big the gun was but if you drop me a line to radworthyboy@gmail.com I could have a look and maybe be of help. I am part of a group of enthusiastic researchers of the 67th Field Regiment RA (known as the Worcestershire gunners) who fought in the 1st Infantry Division in Tunisia and Italy.
Frank de P is correct in suggesting that you apply for his service record but that will take time.
A picture speaks a thousand words, or so they say.

Chris