I agree that 6d is not a satisfactory option as it is a XXXXXX, not a XXXXXXR. I think there is a good 4-letter option, which is quite unlike the other 2.
I have a problem with 41a - "Aragon blocks correct English riding blanket" - assuming the last two words are the definition and it is a B clue, with 'a' being the extra letter. If that's the case, how does sap equate with correct ?
I concluded that the clue had to work as you described. It must be “sap” as a verb, to strike with, or as if with, a sap, ie bludgeon or piece of sapwood, and equate to “correct” as in punish (bodily). But I wasn’t impressed by it
Grahamderek, you are spot on. Chambers has zap as to erase or correct (a fault) (computing). I can’t believe I missed it, but very well found. My humble apologies to Skylark