g'day
From one Pomme to another, things are looking up. It might be a conflict between the Hi TECH compiler and MPLAB. I prefer the HI TECH editor, but the in-built compiler might be confusing MPLAB. Uninstalling everything then just reinstalling MPLAB seems to work.
I am now working on just installing the Eclipse editor from HI TECH to see if the conflict goes away.
Thanks for your help and the comments above were written with a smile on my face and meant in the best of humour!