Vintage Manton Shotgun

I have inherited an old hammer-style double barrell shotgun that I can barely makeout the Manton name in the engraving. I know these were very high quality UK guns and I wonder if any of you Brits could put me on to a knowledgeable gun person to tell me what I have and appraise its value.
Thanks,
Jaydee

A whole lot of them out there on the search engine;

https://www.bing.com/search?q=Manton+shot+guns&src=IE-TopResult&FORM=IETR02&conversationid=

https://www.bing.com/images/search?q=Manton+shot+guns&FORM=HDRSC2

Farmer Giles called. He wants his blunderbuss back.

Jeltz is bored. Waiting for "The Last Watch". GoT was brilliant. Up to now. Only one more episode and then I can wait to (maybe) buy the last book. Used, at Powell's Books.