Cheers guys,
As for the harnesses, I got them for £35 brand new for the pair on eBay, some bloke went to put them in his mini project but for some reason unknown he stopped the project. (Yes they are genuine lol) so I can't really complain there
You can use normal belts with these seats but its not recommended as the belt will not fit you very well due to the structure of the seats. I used this car daily and find it fine. I've set them us so they are a little slack, enough to move my chest if that make sence.