Though perhaps not the earliest MG, this is the car that put Cecil Kimber's small company on the map. A great write-up is here: https://www.mgownersclub.co.uk/mg-guides/pre-war/old-number-one.
Ace was a brand that appeared out of the white metal Abingdon Classics/K&R mix. It's strange how I never got one of these, to go with my 100 or so MGs. But I spotted one at auction along with some other British cars and had the winning bid. Originally gray, the actual car was repainted red at some point and has remained so ever since. This was purchased as a kit (Ace #11) and I do not know the builder, but they did a nice job making the earliest version.
Nice find, Harv. Not one I have in my extensive MG collection. Note the clear relation to the Morris Oxford bullnose which was done by Dinky.
John F. Quilter
Eugene, Oregon USA