1943 Long branch FTR 1953 1/3 Marking

Attachment 93658

Hi all,
Have been wondering what the marking on my No. 4 Mk1* Long Branch 1943 S/N 36L4270 /51 FTR (F) /3 with matching numbered wood and matching bolt. The rifle has been around and has plenty of markings on the wood and metal. On the forestock near the swivel band is a marking I haven't seen. A broad arrow and what looks like R_DD or R_DP _ might be H. Right in front of 323. Anybody have any ideas?

I think it's a ROF (Fazakerley) examiner's mark on the replacement stock. They converted your rifle to Mk.2 configuration during FTR, hence the designation No.4Mk.1*/3.