Hi,
The following may (or may not) be relevant, but store it in your memory banks anyway.
I assume yo are familiar with the strips of electrical cable connectors (described as CHOC-BLOCKS by the Hillman Imp Club) ... small metal, one in, one out connectors, with two screws to connect electric wires, all encased in clear plastic. Just use a Stanley Craft Knife to cut off the required number of connectors. They come in three sizes ... 5A ... 10A and 15A.
The 5AMP connectors will join choke cable inners, and the 15AMP will join choke cable outers ... but they are mutually exclusive, location wise.
Your local HALFORDS will have a shelf full of all the all the components necessary to cobble-up an accelerator cable. For an accelerator cable, I suggest brake cable outer (buy it by the yard) and deraileur (sp?) gear inner cable (about 1500mm long). If you were ever "into" bikes, you are probably aware of all the gubbins that are available.
But be warned, if you cut an inner cable, it will unravel ... unless you solder the area around where you intend to cut ...and then cut by grinding. I usually use a solderless nipple, then coil up the excess. (I do miss my soldering iron on Mum's gas ring).
When I was still in short trouser, my local model shop would sell sell 3ft lengths of piano wire, in various thicknesses ... but it wasn't nice stuff to work with ... though I did ponder on making a woven framework, birdcage-cum--Wellington Bomber style, bonded inside GRP matting. But it's been many years since I could afford a pre-war Austin 7 project. I think I weighted about 40kg last time I sat in an Austin 7 "Special".
602
PS, OT - A wheel fell of my rotary lawn-mower. Barbara to the rescue ... Amazon delivered a pack of assorted R-clips, less than 24 hours later.