Hi Planemike...
You are spot on it is the Napier-Heston J5 Racer.
I found some facts and figures about this aeroplane the other night that prompted this challenge. the 'special' Napier Sabre engine in this aircraft was tuned to put out 4000hp! instead of the original 2450hp. Said engine made up 40% of the total aircraft weight. But the one I found most staggering was that A.E. Hagg and George Cornwall designed her with a top speed of 520mph! in mind. Shame her total flying career only lasted 6 minutes...who knows what might have been.
Planemike you have control
John