Hi Katie and welcome to the Disney Parks Moms Panel.
It's always lovely to be able to answer a question from a fellow UK resident.
First of all, don't worry. The
2017 Disney Dining Plan brochure which is available to view now, lists most of the participating dining locations, but not all of them.
This same situation seems to occur year after year and to my knowledge, each individual non-Disney operated dining location has until the end of the year to decide whether or not they would like to participate in and be included on the Disney Dining Plan the following year.
I would definitely expect to see more restaurants added as participating dining locations before the start of next year and would therefore recommend that you stop by the Walt Disney World website periodically between now and then to see if the 2017 brochure has been updated to include additional participating dining locations.
If you are concerned about making Advanced Dining Reservations at locations which are not listed on the 2017 brochure at the moment, I would go ahead and make them at 180 days out. You can always cancel them nearer the time should certain restaurants not participate in the Disney Dining Plan next year.
Wishing you a magical holiday filled with memories which will last a lifetime!
Emma