Hello Michael,
I just remembered a few details about another Savage Mk1 4T that I used to own. It's probably still in the UKsomewhere, but sadly no longer mine. It is the only Savage rifle I have personally owned that I am sure was a RSAF Enfield Lock conversion rather than one effected by H&H. There was no S51 on the butt, & the back of the body was profusely marked with Enfield examiners' marks. The barrel was a Trials era EFD replacement, as was the magazine. In spite of the many examiners' marks elsewhere on the rifle body there was no mark on the front pad. The forend had been replaced with one of beech, that quite poignantly had had the girl's name 'Yvette' scratched into it. It was a 1942 dated Mk1 rifle & was scoped up with a mis-matched Mk3 telescope. Rifle serial number; 0C4335. I'm afraid I can't remember any more of it, but hopefully this may be of a little use......