Part G only requires that a WC and/or associated handwashing facilities should be separated by a door from a food preparation area. In dwellings, a lobby is not needed, as illustrated in diagrams 2 and 3 in AD G.
However, for workplaces, the Approved Code of Practice (ACOP) that supports the Workplace (Health, Safety and Welfare) Regulations 1992 requires that no room containing a sanitary convenience should communicate directly with a room where food is processed, prepared or eaten. Therefore, in workplaces (particularly in food businesses such as restaurants, cafes, catering businesses and shops selling food), toilets must not open directly C be ventilated to deter air from the toilet moving to the food handling area.