Alright, driving it as normal and I had the CEL come back once with the same "fuel rich" code. I suspect the crimp connectors might not be making the best connection, I reset it back on Monday again and it's been clear since. I also did an oil change in theory to maybe clear out any fuel in the oil that might cause the rich code. Managed to dump half the drained oil onto the floor because I thought I had the pan lined up while I threw the old oil filter away. Oil filter is super easy to get to, almost like a small block chevy, except the filter is in front, and the drain plug is on the back.
Bit of a worry though, no metric wrench fit the drain plug. I needed an 11/16th's which even then wasn't "Happy" so to speak as there was still play. Less than the metric wrenches I tried, but play nonetheless. It still seals so whatever.
Fitted or installed I suppose. "You can't get quicker than a Kwik-fit fitter"
I can't find anything to back up what I said, I feel like I've made it up but I definitely haven't.