If I have any of this wrong, please correct me. Thought I'd pass on the word.
Ebay are going to charge 10% (FVF) on postage as well as on the sale price. This is already in place for business sellers and will come into effect on 4 Sept. for private ebay.co.uk sellers, too. (I presume that means auctions that end on 4 Sep 2013 and thereafter, but could mean paid on 4 sep & after, not clear to me).
One of the side effects is that, for private sellers, the only reason to list P+P separately is if you want to offer different postage options (express etc.). Otherwise you may as well include the P+P price in the start price and guarantee yourself 5* on the postage DSR.