Looking for something in the RAF "249th at War" book

[Airframes]

Yes Bill, at that date the aircraft would still be wearing the 56 Squadron codes, so it would be US-Y. I'll see if I can find a serial from known photos of 56 Sqn aircraft of the period.
EDIT: I first mentioned the code differences in Post#7, in answer to a query from Buffnut.

 

[N4521U]

I never excelled in reading comprehension!
Visual is my forte.
Appreciate the effort on your part, once again.