Perhps the POD might be that UK's AM is really interested in jet aircraft already in 1936/37?
So they issue a request for a jet-powered military aircraft, predominatly a fighter, to enter service by late 1942/early 1943. What impact it might have both on ww2 and early post-war aircraft types and tehnology, on the battles and capmaigns of ww2? How good and useful the fighter might be? One engine or two? Perhaps the 1st generation has straight wing, 2nd gen has swept wings? Usability as a fighter-bomber? When to adopt the type for the FAA? When to make a jet powered bomber? What companies or designers to employ for the task? OTL engines or somthing other? What gets cancelled?