I don't think that there is a conventional coolant temp sensor Kev, that reports that actual coolant temp. Autodata wiring diags & component locations doesn't show one anyway & I don't recall seeing one either.

My understanding is that the cylinder head temp sensor is just a different take on a method of reporting engine temperature.

The sensor is a "fit once" component, meaning it should not be refitted, even if it is still serviceable. The brass tip deforms upon installation & mates up with the aluminium perfectly, for correct heat conductivity. If you attempt to refit one, then there is no guarantee that the seating will be correct & the sensor may misreport.

Regarding the point....

"sensing a much higher temperature than the usual ECT arrangement because of its position, fitted in the centre of the cylinder head between spark plugs 2 & 3."

This was raised on UKAT before & there was some interesting discussion on the subject. I can't find the link for some reason.

Ultimately though Steve, the general, overall (mean average if you like) temperature of the cylinder head, should remain within conventional limits I think, so long as there is coolant present. There maybe local hot spots in certain parts of the head, but where there is coolant, the maximum temperature should remain close to 100 - 120 degrees centigrade.

The cylinder head temp sensor comes into its own though, Once coolant is lost, as it will still report accurately, where as the standard temp sensor can run into trouble if it is not immersed in coolant.