Alan Goodfellow tested NF904 (2nd Prototype) and NP407 (2nd Production) at Woodley. The impression I get from reading his report, which is published in full, is that the aeroplane was a bit of a Curate's Egg. Incidentally Alan (Peter) Goodfellow flew a great range of aeroplanes including nearly all the wartime Spitfire Mks. He told me that his favourite aeroplane to fly was the Mitchell and that his biggest regret was that he never got the chance to fly the Whirlwind.