When Morse looks at the "punishment book" from Blenheim Vale, Benny Toplin's age is given as 8; when Thursday and Morse first interview Benny, Morse asks him to confirm his name and D.o.B. as some date in 1938. This would mean the arson attack took place in 1946 which does not fit with other dates, e.g. the doctor says he started at the school in 1951 (Benny would then be 13) - his daughter has a photo of the boys and they are much younger.
Poster in George Aldridge's cell advertising Benny & Clyde show at Empire Theatre states "Twice nightly - 6:15 and 8:15."
Patterson's ticket for show seen by Endeavour at autopsy says "2nd performance 6:15."
The body of Eric Patterson is found on a railway line. Railways are the jurisdiction of the British Transport Police; they would have investigated, not the Oxford local force.