Okay
I centered the needle and noted the bearing, then out of interest I flew as the needle said. It was still not centered as I aproached sutton bank
If I understand this correctly, you centred the needle and took a reading, then returned the OBS to your original expected bearing (which said fly right) and proceeded towards Sutton Bank.
Sutton Bank is left of the OTR-Kirkbymoorside radial not right so it is little wonder that the needle did not centre.