I don't know the copyright situation so moderators please delete if this is a possible infringement.
p52 of Malcolm Green's book "MG Sports Cars" has this photograph. ISBN 1-85833-606-6
Caption:- The second meeting at the Donington Road Race took place in May 1933 Robin Mere no.33 ............. Robin Mere made a good start but had to stop during the race owing to problems with the supercharger. ...........
Would appear to confirm Cathelijne's posting on the 18th.
Mark, There is another MG Donnington shot on the PWMN site on the following link. I am not sure of copyright etiquette about showing the photo here. Keith http://prewarminor.com/triplw-m-corner-no-80
Mark, Chris Lambert of the Prewar Minor Network is doing you proud. Here is another link with an MG at Donnington in 1933! You'll have to ignore the Hornets!!! Keith http://prewarminor.com/hornet-specials-no-26