Tony. According to "The Hawke History of MMM Competition Cars" (which is as close to having 100% accuracy as human ingenuity can manage) RA0252 came to life at Abingdon on the 29th April 1935 and was painted cream with dark wheels and fitted with engine number 2257AP/R2. The car was raced by Wal Handley at Brooklands and on the Isle of Man on the 6th May 1935, 29th May 1935 and finally on the 6th July 1935, when Handley failed to finish. The M.G. racing ban was imposed on the following day, and nothing positive is known of the car subsequently. All reports of R Types racing can be attributed to the other remaining cars. It is reported that at some point the Works dismantled an R Type for experimental purposes, which might have been RA0252 but this has never been verified. Apparently engine number 2257AP/R2 was discovered to be fitted to RA0251 at some time after the war.
It is now very unlikely that anything new about RA0252 will emerge.