For Jenks and Beagle; the Mk1,-AOBU, resides at NWeald,along with Mk4/T.52(XS228) G-PROV,and XS230/G-VIVM (Mk4/5)(now `resting`).
At a glance differences Mk3-4- longer pitot support strut,sawn-off jet-pipe,and larger cooling ducts on top of the fuselage for the bigger engine(except on G-PROV).
XS230 was at B-D when I was there `68-72` and later to `75/6,as Bob `Ace`Cole was the project pilot during it`s spinning trials,I don`t recall -XS231,the other 4/5 prototype there during my time. 230/VIVM has all the `funny` bits,strakes,chines,stall deflectors/smoothers,and `concrete`,and used to fly with tips when it was at ITPS.