Not being funny, but last time I did a HPI it was nearer £35, sounds like your friend might have been conned twice if the £5 check is also a con

Best of luck, as said above, if real HPI, you should be able to get some form of redress from them afaik.

www.hpi.co.uk says £19.99.

Their website says (http://www.hpicheck.com/newfrontend/guarantee.jsp)
"At HPI, we work hard to ensure that the data we receive and manage is the best available but no data source is perfect. That's why your HPI vehicle check includes the HPI Guarantee. Subject to the HPI Guarantee Terms & Conditions, the HPI Guarantee provides up to £30,000(£15,000 for written off vehicles) reimbursement of financial loss you suffer arising from inaccurate or incomplete information we supply to you as part of the HPI Check. As you'd expect from HPI, the cover is the most comprehensive available today."

Fingers crossed for your friend.