It's something that has puzzled me for some years. The LMS sheet only includes English companies, apart from the LNWR. The Scottish sheet contains LMS and LNER companies The SR sheet contains LBSC, LSWR, SECR, SER and LDCR but not PD&SWJ or IOW. But as us say the English LNER companies and any GWR constituents are nowhere to be seen. The only other exceptions are CLC and the M&GN which do appear on the LNER sheet. In the Defence the transfers were originally produced by PC models and they were bought by the HMRS.
Marc