Hi Michael - there is no casting detail giving the year of manufacture - the machining date which would be very close to the manufacture date is stamped on the flange at the bottom of the block which the sump attaches to and covers - so I don't have those details.
Having said that and going by the casting dates (mm/dd) some where obviously cast in 1940 and used in 1941.
41 Bantam #2621
41 GP #9864 (Karen's)
41 MA #?? (***still need some parts**)
42 GPW #1728
42 GPW #43933
64 Hotchkiss M201 (6v) (Karen's)
Universal Carrier MK1* (Karen's)