Hallmark help please

Lucky find today. This brooch was the only likely candidate in a box of base metal ones. I could see there was a mark on it and genuinely thought it was a costume signature and paid my £1. Slightly unusual catch caught my eye.
It turns out to be marked C&F (something indistinguishable) then 375, an anchor I think and a capital H with a downward stroke on the top left. I looked on line but couldn’t quite see one like it. It’s a very square upright H. Whole hallmark is a devil to photo as it’s tiny and shiny and blurred!.
Also marked/scratched on the stem 3/39.37
Any help welcome.
Thankyou

 

Take a peek at this list of H "date letters" for Birmingham, particularly the 1957 and 1982 letters. I can't really see what's in the pic,just going by what you described.

Any resemblance?

http://www.silvermakersmarks.co.uk/Dates/Birmingham/Date Letters H.html

 

I can't discern anything, but it sounds like 9k gold, Birmingham.
The catch is late 19th century - 1920s-ish, but could have been used later.

 

That's what is confusing. It's more upright than the 1957 but definitely doesn't have the twirly bits on the middle and bottom of the 1982.
I think it's a badly placed 1957 struck on the tilt looking at it again.
Edit- just looked under higher mag and it's definitely 1957. Indistinguishable mark before the 375 just looks like a Pac-man!