If the CAA rules are anything like Canada (CAR's) then any money recieved for the cost of the A/C or anything other would be considered to be a commercial hire. Since you hold a PPL(H) you have to be careful about how you declare any funds you recieve.
I would suggest you contact flyinglawyer for the definitive answer.
Cheers, OffshoreIgor
[This message has been edited by offshoreigor (edited 03 December 2000).]