Third time lucky!
OK, I contacted MGF Bitz and they didn't have one in stock. After trawling t'internet to no avail, to find these second hand is like rocking horse s*@^ , I thought "why not make one"? So this is how I did it:-
Step 1. Get yourself a length of stainless steel catenary wire - it's a scaled down version of wire rope and it's perfect for the job, hardwearing, flexible, smooth surface and the right diameter.
Step 2. Using silver solder (I tried lead solder and both brass and copper brazing rods and none would work) build one end of the cable up. This serves two purposes, one to stiffen the cable and the other to give plenty of metal to work with.
Step3. Very carefully grind down this end until you have a square profile which will fit snugly into the drive socket of the intermediate cable. You should end up with this. -
Step 4. Take the old cable and secure the socket in a vice. With a pair of pliers and a bit of patience pull out the strands one by one until the cable comes free.
Step 5. Cut your new cable to length (1350mm) and crimp on the socket using a 6mm hexagonal electrical crimp tool.
Like this. -
Finished product. -
Step 6. After giving the cable a good blathering of grease, slide back into the sheath and reconnect the coupler under the car. At the engine end, spin the cable by hand until the spindle locates in the socket and ensure it runs freely. Refit the speedo drive.
Step. 7 Take the car out for a little spin and marvel at the wonders of a working speedo and the lightness of power steering!!!
If anyone wants one of these making up because they can't get the gear or crimps, PM me and I will make the odd one or two up for cost. (I will need the old cable for the socket.)