DLP were playing with online restaurant bookings last year, and it seems to be back but only on the Dutch site:
disneylandparis/nl-nl/restaurants
Most modern web browsers will translate the site into English.
Notes:
1. At today's date you can book through to September - significantly earlier than the 60 day window!
2. You don't need a credit card to book
3. The site accepts UK addresses and phone numbers
4. You'll get a confirmation email, albeit in Dutch.
5. Available restaurants are Cafe Mickey, California Grill, Cape Cod, Captain Jack's, Chuck Wagon (Cheyenne), Crockett's Tavern (DCR), Hunter's Grill & Beaver Creek (SL), Inventions (bring a mortgage
), La Grange at Billy Bob's (DV), Plaza Gardens, Restaurant Agrabah Café, Restaurant des Stars, Silver Spur Steakhouse, The Steakhouse (DV)
One small pain is that Crockett's Tavern is mysteriously unavailable for the whole of Friday 23 August which is our last night. But hey-ho, it may become available again or we'll try and book over the phone at 60 days.
Hope this helps someone, and bon appetit!