I would say that all costs associated with a meal service payable as a condition of tenancy are covered by the standard HB deductions in para 2 of Schedule 1:
– Ingredients
– Fuel used to cook
– Staff time planning menus, shopping, cooking, serving, clearing up afterwards
– Equipment used
– The space where meals are served, including heating and lighting that space
All the costs you would have if you were running a commercial cafe.
