Does anyone know this makers mark dating to London? Dated 1939. Images attached. BGLtd. I believe it may be a later Bromsgrove Guild mark. Their silver was typically assayed in Birmingham and they registered a mark like this in 1922 and 1925 in Birmingham but I wonder if they entered a mark for London too? Thank you (Image of two keys shown, both similarly marked).
![Image](https://i.ibb.co/XL2HkBq/BF4002-AA-F71-F-4-B27-A148-F2556-A1-EEF3-D.jpg)