Further to Birt's warning about accepting cheques for eBay items: it is not unheard of for a cheque to be refused by the issuing bank 6 weeks after it is presented. If this happens, then even though your bank let you draw against it after 4 days or so, they will just deduct the amount from your account, send you a letter to tell you, and there's not a thing you can do about it.
Although a cheque may clear within a few days it may not be "given value" by the issuing bank until weeks later. A way to avoid the risk of this is to ask for a Special Clearance on the cheque. This costs you around �12 and your bank will repeatedly pester the issuing bank by phone until it explicitly confirms or refuses the cheque.
For future reference, an alternative payment option is by BACS transfer; it is totally free, totally secure, takes exactly 3 days and cannot be withdrawn after payment is made.