Sorry trigpoint, normally when I make these notes I go back and deal with them within a day or two, but I didn't get round to it this time for various reasons, I also didn't get a chance to walk along the road to confirm if the one way signs matched what was present on the map.

The road was flagged up via a  StreetComplete quest:
https://wiki.openstreetmap.org/wiki/StreetComplete/Quests

As being a possible one-way road due to data from a sat nav system. I've now tagged the other part as oneway=no so it doesn't get flagged up for other people via that quest in future.