Found this on the eBuyer site tonight, checked on HKUD and noticed that the HP655 has been posted tonight by dbrazuk see here http://www.hotukdeals.com/deals/hp655-laptop-212-12-delivered-312-12-100-hp-cashback-saveonlaptops-1495662 for £212.99 (£100 of £312.99) but this is £43 cheaper. Checked the HP site and the HP655 is model (C4Y03EAA) which according to the HP cashback promotion has the £100 cashback on it (see below).
I haven't gone for this myself but hope it helps someone (I know someone will point out that the cashback link mentions the HP655 having only £50 cashback but look at the £100 cashback terms below).
Excerpt from link http://www.hppromotions.co.uk/Terms.aspx?Promo=HP600FEB13AR
Cash back Promotion on Qualifying HP600 series Notebooks (the "Promotion")
These Terms and Conditions govern the Promotion. The Promotion is promoted by Hewlett-Packard Limited, Amen Corner, Cain Road, Bracknell, RG12 1HN ("HP").
Conditions of Entry
1.By entering the Promotion, you agree to the provisions of these Terms and Conditions and to comply fully with them.
2.The Promotion applies to HP600 series (C4Y03EA), (C5C49EA) and (C1N14EA) (together, the "Qualifying Products") purchased either directly from HP or an authorised reseller or authorised retailer of HP within the Promotion Period (see Clause 3 below).
3.The Promotion applies to Qualifying Products purchased between 1st February 2013 to 30th April 2013 (the "Promotional Period").
4.The Promotion is open to residents of the UK and Republic of Ireland, including Northern Ireland, Channel Islands and Isle of Man. The promotion is not open to HP employees, agents, wholesalers, resellers, retail staff, retailers, participating stockists or anyone connected with the promotion.