Very interesting.
Here is a rifle that used to be in my collection; a rifle that had completely unknown provenance, but has exactly the same style of serial number as the one in your photos!
My ex-rifle:
- Long Branch Mk1 action dated 1942;
- No standard serial number or inspection marks - no sign of these being linished off;
- Converted SMLE magazine;
- Fabricated triggerguard, including front swivel point;
- Extended butt, factory oil-burnt tiger-stripe finish;
- Front handguards contain spring studs, apparently as accuracy enhancement.
(Sadly, the current owner has apparently tried to "restore" it to "standard" condition.....)