You have a really well-used WWII pre-Victory British Service Revolver (BSR). From the SN, it likely shipped sometime during the first quarter of 1941. In that condition, its highest and best use would be as a family memento, as it has little monetary value. It could still be a usable shooter, but .38 S&W ammunition is somewhat difficult to find and will be expensive. If you want to replace the lanyard loop, they are frequently found listed on eBay. It's held in the butt with a small pin. It could be OK as a project gun if you wish to try your hand at a do-it-yourself re-blue using a rust bluing kit. Replacement grips which will fit can be found for not much money.