It could be that the Club is trying to squeeze unrealistically high levels of utilisation out of the ac? Hence any knock-on effect of Wx, student, ac delays invariably pushes everything to the right?
That said, there are really only 2 choices. Charge lower prices, maximise utilisation and explain the consequences - or charge higher prices and use a plan which has a lower utilisation rate but which is more easily capable of recovering from earlier delays.
We have now gone for 4 x 2 hour periods (0930-1730). If someone has booked an aeroplane for a particular period, they must arrive in sufficient time to be able to walk out at the beginning of the period and the next pilot should be able to do the same thing at the beginning of the next period. But if it's a 1 hour dual circuit session, the 2 hr window gives the FI a reasonable amount of time to brief and debrief rather than just trying to cram in the hours as used to be the case....
When booking, if you require the aeroplane for a specific time, make it a condition of hire. If you are let down, you should certainly be compensated in some way. Unfortunately it seems that so-called 'trial lessons' which are little more than joy-rides are seen by many as a convenient revenue source. Hardly any briefing to do, fixed (high!) price, FI does most of the flying.... Hence they're probably only too happy to cram in an extra one rather than have your ac sitting on the ground elsewhere whilst you're enjoying your coffee....
I too get very annoyed at pilots who arrive 10 minutes before the start of their slot, then faff about, take-off late and get back even later. Unless it's for safety of flight causes, such behaviour should not be accepted. I had one who swanned in at the start of his slot - the aerodrome was due to close for an hour in 15 minutes' time. So he was told that he had to get airborne before the closure or go away as the next pilot was due in 30 minutes and would be taking the ac on time. He made it - but only just!