Maybe I'm just being dense here, but I'm still not seeing the advantage to someone who actually has a PPL(H) in paying to be a pax. It would be different if you were looking for people who didn't have a PPL but wanted some cheap being-flown-around time.
Also, and I may well be wrong here, but isn't there a prohibition against advertising for people to share costs with in a public way, when flying on a PPL? I seem to remember that the rules went, it's ok to share costs, so long as the pilot pays at least his fair share, no more than 4 people in the aircraft, and the flight isn't advertised. I'm sure Flying Lawyer could answer this one!