Thanks Jon, I am really grateful for your help as always. I will get it copied as soon as I get the details and then speak to Trev about maybe posting it to the Oracle. I'm sure it will be useful to others.
On that subject I found the link to the Canadian guys resume' of the PCM codes very useful indeed, which is why I did the spreadsheet to get an overall picture of why I had a "Check engine light" even though after clearing the minor codes I had no codes showing. His page said that in Canada at least, after 96 the multi plug diagnostics changed from, OBD1 to OBD2 and thus I would not be able to read codes on my 97, not either with a diode nor an analogue multimeter. but only with a proper code reader. I don't know if that is the case with the British models? (maybe someone knows more) however the spreadsheet I did, pointed pretty compellingly to the CPS2 sensor and only CPS2 sensor, as I've changed the dizzy four times which must surely eliminate the internal CPS1. Though I wasn't keen on prodding around with the PCM circuitry,(I'm seriously colour blind so I cant see the wire colours so well) I made an appropriate disconnection and what do you think I found! Instead of 520-580 ohms across the sensor, I've got an open circuit on CPS2, even though I've got no 02 code (CPS2 failure) showing.
Certainly a CPS2 failure ticks all the boxes except the missing code so I have a new one on order which will arrive on Monday. I will get Paul at Berkeley Heath to fit it as arthritis aside, I don't have the lift, tools or time to do it myself. So fingers crossed that's the problem. If it is I will get things back to normal, then look into whats needed to fit the external coil to protect the dizzy in future. Bloody Probes...!