Here are some pictures with census numbers that are close to your engine’s census number. The second picture shows some brand new bikes from this contract being rolled out of the Birmingham factory.
And the pictures below show two bikes with census numbers that are close to your frame’s census number. Both pictures seem to be taken in Italy (?) or Greece (?), considering the short sleeves. The bike in the second picture is captured by the Germans.
There’s also another number on the headstock. And there’s a Hellenic Crown next to this number, meaning that your frame once belonged to the (post war) Greek Army. You can find more information about these Greek Army numbers here and here