I got mine from Venhill cables.
Discover Venhill's UK manufactured vehicle cable and components. All parts from a cable conduit, wire and fittings required to make up a control cable.
www.venhill.co.uk
I keep a spare inner cable in the car so it can be fed through if one snaps. Also keep several spare solderless nipples in the car as the soldered ones can sometimes pull off.
Cheers
Mike