Google Woolies Trim. They do some decent renovation kits.
A top tip for leather seats is to use Hydrophane oil to restore flexibility and strength to dried out leather. An old car I bought soaked up so much that I was convinced it was going through into the stuffing, but I tried using it on leather that was stuck direct to aluminium and that soaked up a similar amount. It evened out some bumps where the leather had rucked up in the sun. Occasional use after the first go and still in good condition years later.