Locket with unidentified unusual Hallmark

[treestump]

Hi, i have been searching high and low, i bought this second hand a year or so ago, i had lost it and came to find it again in drawer so out of curiosity posted it in facebook group, a very knowledgeable lady mentioned to me she thought it was gold, but so far no one has been able to understand the hallmark / stamp.
 I have tried other forums too, with no luck as of yet, i have tried endlessly googling but as someone with not alot of knowledge of jewellery i came up with dead ends. I just can't make out what the stamps suppose to be of? The lady who thought it gold did mention it could be an asian hallmark?
  It is a locket and does open up. Any help much appreciated. I have no idea how old this is either, so apologies if it isn't antique.

[treestump]

This is a photo of the hinge, also i live in the UK, England, and this was where i purchased it, however it doesn't look like an English stamp / hallmark to me.

Thank you in advance to anyone who may be able to help.

[mart]

Is there anything on  the locket itself ??  Problem with the mark being on the links or the chain is that they are not part of the locket !! Chains and such are always separate and usually purchased in bulk !!  Even now jewelry stores do the same thing !! You can purchase a chain and then pick what you want to go on it !!  You can take it to a jeweler and have it tested for gold !!  The mark on the chain link does look to be Asian but its hard to tell with this mark !!