How many Miles M.20 fighter prototypes were built?

[Larry]

Miles Aircraft at Woodley are said to have built several M.20 types. The first M.20/1 was only a wooden mock up and possibly had a gull wing and retractable undercarriage and is said to date from September 1939? Was this a private venture? Was this the aircraft seen by Secretary of State for Air, Sir Kingsley Wood, in the early months of the war. Most references suggest the M.20 fighter was conceived only at the state of the Battle of Britain?

There is mention of a Contract B140247/40 which doesn't look very accurate? Can anyone help on this

Then after it is said that 65 days from the Specification that an M.20/2 (now with fixed undercarriage) flew on 15th September 1940, under Contract F.19/40. It had the serial AX834

After that there was M.20/3 potentially for the Fleet Air Arm, with a serial of U0228 and later DR616. The RN Specification was N.1/41. I thought this was the last M.20 but I have seen drawings and spec for a Miles M.20/4?

Any help gratefully received

Larry