FFS - ok, panic over, all sorted.
It seems that the ECU wasn't saving the TPS settings or I was somehow doing it wrong. After the last engine run, I noticed that it showed only 30% travel (in the Emerald software) when I was almost at full throttle. So I did one last reset and I had to come in to do some work.
Went back out after work and started straight up, idling as normal.
I dunno - might go again, probably at 4am when I need to leave for Wales
Thank you all for your suggestions