This is where i would split the share between 5~6 friends thus dividing a £40k purchase price evenly at £6500 each
Thats the normal way it is done. Don't think of it as a "Joining fee" as you have mentioned above, it isn't, it is the capital purchase of a share. Remember it will not be "your" aircraft anymore, it will be jointly owned.
the anual costs (est 6500~7000 pa) would cost 6 people £95 pm each
.
That figure seems really low. Have you thought about annual insurance, hangarage/tiedown costs, and the killer - annual maintenance/inspection, which could easily be £10K alone? How much research have you done in this regard?
then the cost PH = whatever the cost of fuel!
What about the cost of 50 hour inspections? What about a replacement engine/propellor fund? If you don't build these into your hourly rate then your group is going to face bills they hadn't budgeted for every 50 hours, and a £20K engine replacement bill at some point.