Well the new height corrector turned up and I managed to fit it on Friday, in between the hail showers. finished fitting it and it all seemed to work fine. Then just before I took it off the ramps I had a final check underneath only to find the damn thing was leaking again.
It turned out to be the small length of rubber tube which holds the plastic return pipe onto the height corrector had a very small split in it. I managed to trim off the split bit and put it back with what was left of that pipe. If only I had realised that in the first place I could have saved my self several hours and £76.
Still at least that is one part that shouldn't go for a while.
Thanks, for the help
Rob