So finally i got around to tweaking these.
Can anyone explain why (after analysing how the overrides got on), on 3 out of 4 occasions my WR1 who I'd moved to WR3 in Shotgun Normal 113 appeared as WR2?

Best guess:

The WR1 or WR2 was tired, so he subbed out. When that happens, everyone moves up a spot.

This.

Thanks that's what I thought but it wasn't the case. I'd set wr1 Kingsbury at wr3 position for shotgun normal. Evelyn wr2 at wr2 and medlin wr3 at wr1.
But in those plays medlin did play at wr1 however evelyn was at 3 in slot and Kingsbury at wr2!

All very confusing so I've reset them for the moment. ...