Thanks for the reply Twiss. Checked hoses and cannot find any leaks. Got the tickover screw backed right off so it's no longer touching the lever it's meant to control, makes no difference, still running fast and eratic. Took it for a spin round the block and it runs fine apart from the vibration I mentioned in an earlier post. It's only when I come to a junction or pull over the engine races. It's doing my bloody head in.
Scottie, thanks for the advice. Will order temp. sender unit next week from main dealer. Don't know why I didn't think of this before.