Thanks for the help on the speedo cable. I went to the breakers mentioned and sure enough they had a Samba Cabrio in the far corner.
I needed the car lifted to get the speedo cable so am going back on Monday morning.
I did, however, pick up a few other bits.
My gear change was VERY sloppy, the lever would move almost to the opposite side of the car between gears so I thought the problem was the bush on the base of the gear lever, operating the top rod.
I got the gear lever from the breakers, but on removing mine, I found the rubber bush was fine.
when I went to look further, the entire top rod was very loose and in fact not connected to anything (maybe moving the lever disconnected it).
I looked in my Samba Haynes manual and there is no information on the fitment of these gear linkage rods, just a paragraph about fitting a spring if it is not already fitted.
If anyone can explain how the linkages and rods fit together so my gear stick is attached to my gearbox I would be very grateful!!!
Mike