Factual error: When flying to France to have talks with the French premier a C47/Dakota is shown in the background intimating that it was the plane he came in. The C47 did not enter service with the RAF until after this period of the film with Lend Lease.
Suggested correction: The aircraft could just as easily be the civilian version, the DC-3 which first flew in 1935, and was pressed into RAF service and repainted.
The RAF did not requisition civilian DC3s or DC2s. It is well recorded that Churchill flew to France in May 1940 in a de Havilland DH.95 Flamingo. Only 16 were built - de Havilland cancelling DH.95 production to make more Tiger Moths desperately needed for pilot training. The DH.95's were cannibalised for spares, the last scrapped in 1953, so the film production company may be excused for their C-47 use. Though a Lockheed Lodestar may have been a closer simile.