There has been a number of conversations on the subject of the cables becoming no longer available (which is shocking btw) but no one has come forward with an alternative solution.
I would suspect they could be re-made but of course the supplier would need a good set to base their pattern on.
Good luck.
I know the company you are referring to Matt, think automotive are also in Isleworth which is the branch fatty Brewer went to in the Lambo episode.
For the gear cables, contact Ed at Christian Lewis. Last time I was there they had just replaced the cables on a manual 4200. I asked him where he got them and he just smiled.