Thanks to Chris Lambert and the Prewar Minor Network I think we identify that it is a University Motors 1930 Foursome Drop Head Coupe! Photo attached is clearly the same type of body but different Reg number.
The Owls Head museum has six MMM cars: the MG M Coupe from the video plus a J2, two L1s (one a Continental Coupe), a PA, and a NA. They also have six more MG's incl. the TD from the videos an SA, A VA and three more T's.