Fifty150 thank you for such a comprehensive and informative reply.
I broke down the other day, coolant temerature sensor failed. The CEL/EML did not come on. New sensor got me going again. Mechanic read fault codes and cleared them.
Subsequent to that, out of interest, he read them again couple days later. U1262 and B1318 present.
I have now got ForScan and a USB ELM327. Not used it yet though.
GBL, oil pressure indicator is a LED. It comes on in startup position just like it should and goes off on starting.