Bren serial numbers.

[Ben Grun]

Just to add the serial of my recently acquired INGLIS 1942. MK1M Bren. IT5341. on upper and lower receiver, near butt. Also has New Zealand serial to all black barrel , NZ 5839'. plus, opposite barrel nut, 'NZ3543'. which is stamped AND engraved.
Came with chest (no bumper bar on front) this has '5839' painted on, same number as barrel.
Seem to be lots of 'JI' Markings, certain parts not sure about ( a newbie,my first Deac and probably the last after the recent UK/EU law change )
VERY pleased with purchase overall though has an odd bipod! looks like it started life as an adjustable one, but is now non adjustable... worn finish doesn't match rest of gun which is very good so, at some point in its life it has acquired a replacement I suppose. cannot remove as barrel is now fixed? not that it matters, just never seen another bipod like this.......so far.
Can anyone tell me date of manufacture (month) and anything about its history?