Help to identify blind stamp on portrait miniature. Royal connections?

Sep 2018
4
Malvern
I'm researching a 19th-century portrait miniature (circa 1830) and I've discovered an interesting partial blind stamp on the back on the frame. It consists of the St Edwards Crown accompanied by some initials. They're tricky to decipher but the last letter (under the embroidery) is a W. Could it be a family coat of arms perhaps? I'm guessing that it's not simply related to the maker of the frame as I can't find anything comparable. Any ideas?

IMG_7183.jpg
 
Sep 2018
4
Malvern
Thanks Dave, that's useful. Yes, it's from the UK and it's a watercolour on card of a lady. I'm not all that familiar with miniatures and haven't seen a blind stamp from a framer before but I agree that it could make sense. I'll check the NPG.