Roast meats. In a baguette or roll, with traditional accompaniments (pork and apple, Beef horseradish, chicken stuffing) and side order of mini roasties.
Nut/mushroom roast for veggies
Very fast. You stand there with a few roasts in front of you and sauces and make them to peoples spec.
No brillaint, not hugely innovative, but they sell, they are fast, they are simple and the margin is good.
You open for breakfast with sausage and bacon, etc and switch to lunch menu at 11. Close at 3,clean up, prep next day and home in time for tea.