I’d like the guest to be able to let us know of any dietary or mobility requirements when they book with us. What is the best way to achieve this on the booking form?
There is the ‘Notes’ field on the Checkout page where a guest can specify the needed info. You can also rename the ‘Notes’ field (as any other system text of the plugin) to ask guests to specify their dietary or mobility requirements. Here is the article on how to change text in the Hotel Booking plugin.