Dating Villiers engines

How can I date Villiers engines and there is also a list when certain types are created?

The Villiers of my son are: a Midget, nr. 7B 598, a Midget, nr. 3B 053, a Mk 10/2 HS, nr. 319E 8640, a Mk 20, nr. 755-366504, a Mk 15, nr. 576C 54733, a Mk 10, nr. 001C177468E a Mk 12-0703, nr. 114494, a Mk 10, nr. 347A139009D, a Norton-Villiers D07 10, nr. 01 1580, and a Norton-Villiers D07 10, nr. 01-12196