I've just bought a London Waterloo to Ryde Hoverport ticket, using the bus from Portsmouth & Southsea to Southsea Hoverport. On my return journey, how strict is the restriction of which hovercraft and bus I use? Is it strictly timed, or is it like an "and connections" reservation where I'm likely to get away with catching the previous hovercraft on the return journey - if I'm allowed, I'd like to be a bit early on that stage to reduce the possibility of missing my booked train if there's any delay on the hovercraft/bus. (Yes, I know if there is a delay I'm allowed to catch the next train, but I'd rather be on time than claiming delay repay.)