Leather Sofa Restoration - Advice Needed

GrrArgh

Hi,
I got given 2 leather sofas, however they require restoration & tlc. The problem is I'm not quite sure how to restore them. They aren't high quality leather (I think they were bought from Argos), so I'm not sure if they are bonded etc...
The leather is patchy, in some areas they are light brown and other places are dark chocolate (large patch area's). When I used leather cleaner the lighter brown patches peel to reveal the darker colour. The peel is sort of like eraser shavings.
Can anyone tell me why this is happening? And how do I easily get them back to one shade? It's almost like a film coating peeling off.
If anyone can help, it's would be much appreciated.
Thanks

Working_Mum

Are you absolutely sure it is leather??

I was given a sofa once and it wasn't leather but a very good "faux" and i couldn't ever get it looking really nice.

GrrArgh

Hi,
Sorry I took so long to reply.
I pretty sure it's leather, at first I thought it may be bonded but I've been assured it's not. I think is more likely to be cheaper, though it could possibly be split leather.
I still haven't solved this problem. I have however found out that its called Colour Separation.

Thanks