QDM - I fully agree, it's a no-brainer. Some here seem to think that if instead of the £65/hr Cub, you had a £750/hr newly-minted Oki-Koki 9000 twin-turbine helicopter, then it would be "commercial" because of the benefit to a low hours pilot in getting "high-value" hours in the logbook.
I don't agree, as it's not possible to give a future value on those hours. Fred may have no interest in hours building for a CPL/ATPL, for example, but Jack might - so if you can't contact Fred and so call Jack, does it mean it's commercial - I don't think so.