I stumbled on this excellent coffee stop! Large, comfortable, lovely rural views, a very good selection of food including breakfasts. They already cater for large existing cycle clubs once a month (Marlow & Richmond) when they put on a buffet spread for about 80 riders. Also a nice farm shop here for meat & vegetables. Definitely a hit!
If you approach this coming from Maiden's Green down Hawthorn Lane it can seem like a bit of a punt, but persevere down the relatively tame gravel track and you'll find it at the end (and the exit pops you back out on the main A330 road).