Although it says H&H I suspect they're highly butchered Purdey rings, extensively reworked into civvy mounts by H&H after the war.
Harlton, if you can find a Winchester A5 or B4 scope I have some reproduction Whitehead Brothers mounts available at the moment - just pm me if interested.
I do get batches of PPCo & other mounts made periodically, & am currently awaiting a small batch of H&H mounts (bases & rings) for the SMLE/Aldis. I know not exactly when they will be ready, but hopefully by the end of this year. Don't have any PPCo's at present, but they are also on the list to get done again in due course.
ATB.