Sounds about right Dannn, the police website merely states
http://www.askthe.police.uk/content/Q533.htm
Question Q533
Can my car be driven by my friend if he has a fully comprehensive policy that allows him to drive other cars if my car is not insured at all?
Answer
It is always best in these circumstances to talk with your friend's Insurance company as these are the people he/she has entered into a contract with.
Most companies specify what you can or cannot do and if it says on the insurance that it allows your friend to drive someone else's car then he/she would be covered. However he/she must read the full wording of the policy document and of the actual certificate to ensure that this is exactly what it does say.
There are a number of pitfalls with this situation (for example, the level of cover may only be third party) and the importance of disclosing the potential risk to your insurers as part of your contractual liability cannot be stressed enough.
So another grey area!
I would call HIC and check with them... but they are closed for the weekend