I've often driven past the Ambassador Training Restaurant which is located within the Ryde TAFE at the Le Corden Bleu school. The bookings availability appears to be mostly mid-week slots, some at dinner time and some at lunch time. Just after Valentines Day, I manage to get a slot on a Monday night. It's a three course meal for $44, plus any drinks you order. I think that's quite good value and you are also supporting trainee chefs and staff.
