I'd agree on mid late 40's due to position of mudguard mounts and 'pencil' -ish rear stays, looks decent quality, headclips still in use in 1947, my Raleigh Lenton Clubman still has it's original one fitted!
These are commonly known as path/track frames or derivations of that...funds were more limited so you'd basically have a 'track' frame fitted with mudguard eyes so you ride it all year round, common to ride to track meeting on clinchers and fit tubulars carried on bike then race having first removed brakes and mudguards, refit after race and ride home!