It gets a bit complicated but it can be done.
Firstly, you and the student need to be both members of the same club so you will need to set uo a club and that club will have to be an RTF.
You can then hire the aircraft to the club at £xx per hour dry i.e. a rate that does not include fuel, maintenance, insurance etc etc. The Club agrees to pay those and you have an hourly rate and probably a monthly standing order to cover fixed costs. You are an equal member and are thus required to pay your share and you have equal booking rights with all the other pilots. There are airworthiness implications and insurance etc etc
The hourly rate paid by any member for the aircraft will not depend on if it is being hired by a PPL, Flown dual with a student or solo by a student.
You must pay the same rate as your fellow members and you are jointly responsible for all fixed costs etc etc.
The whole thing is about you being able to honestly show that the student does not make any payment for the flight training provided by you as a PPL.
Note that you can charge for all ground training and briefings.............but you would be found out by charging £20 per hour for briefings and making an exercise 3 pre-flight brief last 1 hour.
If you charge an attractive rate for the aircraft and it is something like a nice C172, expect quite a few PPL (or higher) holders to join.
Then you have your students - unless you have independent means, you have to work and thus your availability is limited....basically part time. You find it hard to get instructors to "work for you" because you can't pay them and after a while, your students drift away to where they can get more regular training at not much if any extra cost.
On the other hand getting the CPL, means you set yourself up as an RTF and charge people to train on your properly certified and insured aircraft.
God does that for some reason make the CPL seem worthwhile?
Regards,
DFC