http://www.dynamixdyes.com/) but I think they're also on ebay so I guess you could buy from there if you prefer. Unfortunately my dad managed to knock over the pot and we lost about half of it so he ended up buying me another bottle of dye to replace. I still haven't got round to doing the drivers seat (although the bolster has now been retrimmed) and once I've done that I might move on to do the back seats although they're in pretty good condition.
When I got the repair set I was wondering whether to save the money and use the autoglym cleaner and conditioner I have in my garage. I ended up going for the whole set and it was the right descision: the cleaner is the best I've ever used and the conditioner is excellent too. (mmmmm leather smell!)
Also, Sam, I know what you mean they were pretty bad. I've not seen many sets of 8 series sport seats come up for sale though and for that price I was really struggling to say no! I was worrying what I'd done all the way home from the scrap yard but now I'm slowly getting there with it I'm pleased I took the risk. I think!