On recent holiday in Cornwall, decided to visit Truro, on approaching city saw sign "for Truro use park and ride". Seemed like a good idea so in went and parked. With two kids 16 and 10 a family ticket should do. Wrong! 16yr old classed as adult so that's a family ticket + extra adult. Duly paid our dues got the tickets from the machine. Off to wait for bus. Snag we had our little dog with us not allowed on site or bus, no sign was seen before parking or buying tickets as it's a small notice on the door that opens to let you into ticket office. Not had this problem using any other park and ride or bus.
A few years ago now, we used the Park-&-Ride at Three Mile Stone to go to-and-fro to Truro. Having bus passes it was free at first, then we had to pay a concessionary fare.
The one at Penryn for going into Falmouth was good at first, then that all changed. So we used to park at the start of the 'scenic route', overlooking Falmouth docks, and walk round into Falmouth.
Had a similar problem in Gloucester some years ago. No dogs on P&R, so drove into the city and found car park above shopping centre. Only way out of car park was through shopping centre and - guess what? No dogs allowed in shopping centre!