Buttstock markings on my No 5

My newly acquired Faz 1944 No 5 carbine has had the stock refinished (DARN IT) but most of the markings on the left side of the buttstock are readable. I would imagine that they are unit markings. If anyone could help iI would appreciate it. Sorry for the poor photo.
B and (unreadable letter)
(over)
S
(over )
3
(over)
55

Thank you

40 B=Base W=Workshops. S=Singapore 3= March 55= 1955.

Ex British Army No5 from Malaya. Thyat's seen a bit of service.

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GREAT information ! Thank you very much sir.
Knowing some of the history of our individual firearms makes them that much more valuable and cherished. I appreciate it.