Have a look around the areas of brake and clutch controls, where there might be unused holes where provision is made for LHD/RHD. Hopefully you might find one with a grommet in it, and can replace that with a cable and grommet to suit.
I have looked under the glove box but not under the carpet. There's not a lot of room under the dash, a job for the weekend I think. Thanks for the help.