Splendid story Genghis. I did not have the privilege of knowing Miss Welch as you did, but that anecdote sounds very much in keeping with the character that emerges from the recent obituaries here and elsewhere.
I have not yet come across any new or second books about the exploits of the ATA pilots, although some must have written memoirs. Off to alibris and abebooks I go....
Two digressions:-
(1) Someone designed an amusing scenario for the Microsoft flight simulator in which you are in the circuit in a Tiger Moth and are set upon by between two and four 109s with unfriendly intent. Your mission is to stay alive for five minutes, after which time a bunch of Hurricanes turn up to save your butt. With practice you may even get a sneaky kill by provoking one of the bad guys to stall and spin in from treetop height.
(2) A friend of mine doing pleasure flights out of Waltham in a yellow ex-RAF Moth recently enjoyed a turning fight with the pretend Me 108 which lives at Waltham in Luftwaffe colours, to the delight of the passengers in both aircraft.