This site may have what you need-
https://www.deadspartan.co.uk/shop.p...=1#prettyPhoto - 3 Queens Crown badges listed. I should think it is hard to be sure which is which unless it is easy to compare size. Badge on page 1 is not listed as a beret badge, others on later page are, so the one on page 1 should be the larger badge. If thinking of buying, hopefully someone collecting to this regiment will confirm if it is what you need. Regards, Paul.
Might be an idea to post the full picture of your grandfather. I take it there is no chance he was an Army Cadet before his national service?