My maternal grandfather was an enlisted radio/wireless/electrical technician and arrived in the UK in June of 1940 with the RCAF squadron. He had some pictures of 303 squadron. 1 RCAF and 303 were assigned together to work in the same wing while he was posted there, and their bases were close together, about an hour transport each way he said, and he was among the RCAF ground personnel that worked on the Polish squadron aircraft and systems when required. (Croydon and Northolt).
They had some successful days winging together, 1 RCAF and 303 destroyed 2 JU88, 4 ME110, and a 109 on Sept 27 1940, fighting vs 70 German aircraft total, with one RCAF Hurricane loss, the pilot KIA.
I'm glad to see more films such as this being made.