Expedite,
I presume your concern is that the CAA will look on this as being illegal public transport, because you're getting a valuable reward of reduced rate flying.
I don't think that the reduced rate would count as valuable reward, because you also have reduced utility, in that you can't choose where and when to go! You must go to/from the maintenance facility on the particular day.
That's why you would be getting the reduced rate, not because you were doing them a favour.
I think you should be ok on that.
I ferry aircraft all over the UK and Europe for people. I would never expect to have to pay to do it!!
Bose, I don't see many low houred PPL's being asked to ferry aircraft across Europe
There might be a reason that they prefer you to do it for free, rather than a low houred PPL to pay for the privlidge
dp