I have stories 5 of the Harry Potter audiobook cd's (Philosopher's Stone, Chamber Of Secrets, Goblet Of Fire, Prisoner Of Azkaban, Order of The Phoenix). These are the spoken word stories read by Stephen Fry which I would like to swap for other audiobooks.

However, my discs are really good quality copies so you wouldn't know the difference when listening to them - obviously, I would add this info when listing them.

But before I list these in the audiobook section, I thought it best to check if audiobook copies ok to be swapped?

I think you should check with Admin as to the legal aspect of this. 

If they say ok you should make it clear in your description that they are copies as some people may have equipment that won't play copies - my stereo at home doesn't like copied CDs.

This isn't legal as these are unofficial pirated copies, so I don't think Admin would let you list them.  Definitely contact them about it before you list them if you want to double-check.