If you plan to do the seats yourself it is not too difficult. The leather may be in need of a 'feed' so you could try a light application of saddle soap and then buff up when dry. If you have the reversed hide inserts ( suede), you will need to 'lightly' sand-paper these panels to restore the colour and texture. Make sure you use sand-paper which is light in colour NOT emery paper as this can leave dark marks on the suede. I use this method on saddles and seems to work really well.
There is a firm in Bradford if you get really stuck, they are A.S. Pickering Tel 01274 724000, I found them to be really helpful, the guy I spoke to was David Brown. But he's not really local to you. There is another chap in your area Ian Whittley who has his finger on the button but he cannot be contacted for a few days, if you would like I could contact him in a couple of days, let me know .