Not the Red wire in the above photo, it is a random piece of wire that has been attached to the starter's stud, it is much too thin to be usable.
Mitch Klempf in the US lists and pictures standard Triumph electric starter cables. However, he will relieve you of the best part of $70, plus p&p, then HMRC could take a bit more when the cables arrive in the UK ... if the Co-op cut corners like NVT did on the the T160, the standard cables could be too thin for the current drawn by the starter ...
I use Vehicle Wiring Products' Flexible battery and starter cable in various sizes, suitable for 12V and 24V automotive, marine and solar power applications., "196/0.40 25mm sq. 9.8mm O/D, 170 Amps" selected from the "Size" dropdown. VWP will also make cables to order, which I find easier as they have the necessary special terminal crimping tools. Note the starter stud might be an odd 7 mm o.d.
The cable between the battery -ve terminal and an engine bolt will also need to be the same wire size, just with ring terminals to fit the battery terminal and the selected engine mounting bolt.
