The overflow tubing from the expansion tank is is routed down and under the engine and is tied onto another cable on it's way down. Yesterday I replaced the overflow tubing and yanked it too hard and the cable which it's tied to came away from it's housing. I pushed the cable back into it's housing and hope it's ok! Question-what is that cable? (seems to be some sort of sensor) And what is it attached to? I looked in my Haynes manual but found no clues. Many Thanks.

Do you have a picture of said cable? My overflow just hangs down by itself, not tied to anything. It is/was a fairly rigid piece of pipe though.

not a great picture but hope it helps. If you position your head just to the right of the rad cap from above and look directly down, your eyes will fall on the cable in question..cheers

Ok, I'm 90% sure that is the speedo cable. If it is (has a metal collar around it that screws to the case, and cable pokes down inside) then you may only have to push it in, and do the collar up.
If the collar only spins and doesn't tighten, then you need to adjust some other stuff. That's unlikely to be the case though.

Yes you're right..just drove it with cable disconnected and speedo doesn't work. When I push it back on it seems to stay in place ok so won't worry about it too much unless it ever comes off of it's own accord..doesn't screw on as far as I can make out but I'll take a better look when I have time.

Thanks for your help.