Like many Teddy Petter designs, it had its serious flaws. The main one in this case concerns the advisability of routing exhaust pipes through the middle of fuel tanks on a combat aeroplane
That exhaust system was on the first prototype, and only retained for a very short period of time, after which the system was modified to a shrouded ejector exhaust as seen on many Merlin installations. An impetus to the change was probably an incident that took place on 10 June 1939, where shortly after take off the aircraft rolled viciously to the right. The right aileron had gone to an uncommanded full up deflection which the test pilot, Harald Penrose, was able to control by full opposite aileron. A judicious landing was then made without any effective aileron control. The right engine exhaust duct and insulation had failed allowing hot gas to burn through the aileron push rod.
As for Petter designs and their flaws, remember he did design the Canberra, and Westlands allowed him to take the design with him when he left their employ.
Whirlwind was not a good fighter to have to bail out of due to the high tail getting in the way
For bail out the tail is in the ideal place, high and out of the way. Mythology has the P-38 tailplane being an impediment to bail out also, which was not the case.
Exactor was a throttle control system which used a hydraulic type linkage instead of the usual rods/wires/levers
The Exactor system was used on the throttles, mixture, prop pitch, undercarriage, flap, wheel brakes and fuel cocks.