The MGA evolved from a specially-bodied TD that raced at LeMans, that looked very much like the MGA that came later. Syd Enever was unhappy with the TD chassis since it meant the driver sat too high, so he drew up a new chassis where the frame rails were much wider apart and the seats sat inside the frame rather than on top. This became the basis for the MGA. MG was prevented from putting it into production in 1953 because BMC feared it would steal sales from the Healey 100, so they rushed the TF into production as a facelift on the TD. However, the old-fashioned looking TF was a commercial flop so MG were finally allowed to put the MGA into production in 1955.
I have never seen the car in your photo before but suspect it came later and was styled to look like the MGA coupe.