GWRJ 66 has an article by John Copsey covering the working of the Dukes. By Jan 1940, they had all migrated north and eastwards, with allocations at Didcot, Gloucester, Cheltenham, Tyseley, Wellington, Shrewsbury, Oswestry (all one each) with two each at Machynlleth and Aberystwyth. (They were certainly very uncommon in S.Devon by this time - my old chemistry teacher at Torquay Boys Grammar School (who was himself a pupil at TBGS during the war) told me many years ago that he was roundly disbelieved when he copped "Isle of Jersey" on a Kingswear local c. 1943)
I doubt that they would have found much favour at Newton compared to the Bulldogs - the survivors must have been very tired mechanically by this time.
There is a lovely photo of 9083 (ex-3283) Comet (often graffitied in comet ax!), in Swindon roundhouse, dated summer 1948, in Great Western Pictorial No.3. It appears to be newly painted green (no tender insignia and a W marking under the number plate) so you could just about stretch reality and send her west for a final fling.
She was withdrawn from Oswestry in December 1950.
9084 "Isle of Jersey" lasted until April 1950. 9089 was last of all, being withdrawn in July 1950.
I wonder how much time they spent actually working in their last few years?