The creeping issue I think was mainly my lack of understand on the software interface. I have since learned that the value for offset, may not be the actually value saved. You can type a value in two 3 decimal places, and click apply, and it does save. Simply with playing with this value I resolved my problem.
Yesterday I spent the afternoon cleaning out the sump where all the coolant is kept, There must have been an inch of 20 year old crud in the bottom Not the nicest of jobs.
Can anyone recommend a coolant fluid?