Just thought of another feature..... the ability for restaurants (and maybe music venues, event organisers etc) to be able to take bookings.

Again, there are lots of ways to add to the basic booking form; being able to limit the number of places sold (to prevent more bookings being taken than slots available), being able to select from standard or premium places, being able to take deposits up front etc. Some of this might end up needing the creation of a back-end admin panel for the website owner - another possible chargeable extra which creates the potential for all kinds of new expansion !