I think that explains: from www.ps3.com
In the UK and Ireland, a Value Pack consisting of a 60GB PS3 with extensive backwards compatibility and two first party titles will be on sale at a price of 499 (£349). Remaining on sale while stocks last, the 60GB model represents outstanding value for the keen gamer wishing to upgrade to the High Definition capabilities of PS3. Once stocks are exhausted the new 40GB model will be the only one available in the SCEE territories.