Model Variants (Including Prototypes)
Heyford - Base Series Name
Heyford Mk.I - Initial production block; fitted with Rolls-Royce Kestrel III engines of 575 horsepower; fifteen examples.
Heyford Mk.IA - Revised variant with four-bladed propeller units; twenty-three examples.
Heyford Mk.II - Fitted with Kestrel IV series engines of 640 horsepower; sixteen completed.
Heyford Mk.III - Fitted with Kestrel VI engines of 695 horsepower; 70 completed.