[British-cars] MOWOG: Group, garages or arbitrary G?

[pethier at comcast.net]

Some say MOWOG stands for
MOrris WOlseley Group

Some say MOWOG stands for
MOrris WOlseley Garages
(citing the formation of a company with that name in 1938, others claim there was no such formal name)

Others say that the G was added arbitrarily to symbolize MG.

Is there any actual historical evidence to show which of these stories is true?  Not Wikipedia evidence, but real-world records?

Let the games begin!