Thanks Ron - I had a read up from your link and then found some others.
You are right it is a PT100 and is 1.5mm dia but I still cant find any recommendations on how to mechanically connect it to the leads, cant solder it, cant weld it, cant use a chocolate block in that heat? puzzling. It is not going inside to read EGT but on the outside of the exhaust and under a hear shield.
It seems there will always be an offset on the voltage so I have included a circuit that hopefully removes the offset so it can be easily displayed on a meter (an SP300 to be precise) as it is part of the same project as the pressure sensor, it will be switch selectable which sensor is monitored.
Do you think the circuit will be OK