1940 School again…

303 Sqn arrived at RAF Northolt on the 2nd of August 1940. The very next day they commenced their training in the Miles Master, a trainer that provided a fast, strong and fully aerobatic aircraft that functioned as an excellent introduction to the high performance British fighter aircraft of the day: the Spitfire and Hurricane.
By the 6th of August the pilots were already in Hurricane Mk Is. By the end of August, the unit had received an initial complement of 18 fighters.

polishsquadronsremem..m/303/303_story.html

en.wikipedia.org/wiki/Miles_Master