1939 Enfield Bren - a spot of help please

[lugerfan]

Thanks Peter,
The serial number on the upper, lower and barrel nut is A7534 in what i am pretty sure is the original font (early to mid January 39 production?).. The barrel bears the same number along with a struck out b?537 (looking through a magnifying glass I think one of the mentioned rewelded deact and holes goes through this as the b is partly formed and the number is its a bit feint) there's also a '39 date on the barrel, which makes me think it's a b block originally

There are a lot more markings on this one than on my 43 dated mk1, All these marks really do tell a story don't they.....