Ventilation Regs open plan kitching /living

Hi,
we are having discussion with Builder and Architect whether our newly contructed living/dining/kitchen extension requires a permanent background vent or not.
We have no "tricke vents" in the windows.

Architect has quoted TGD-F in support for not needing permanent background vent...

1.2.2.3 For wet rooms, e.g. kitchens, utility rooms, bathrooms or rooms with sanitary facilities (without bath), where mechanical extract ventilation is provided and there is no provision for general ventilation by means of controllable background ventilator and no provision for purge ventilation by means of an openable window, the mechanical extract ventilation should include an automatic 15 minute overrun (after switchoff). In the case of a kitchen, utility room or bathroom without WC, control by humidistat is acceptable as an alternative to 15 minute overrun. Any automatic control should have a manual override to allow the occupant to turn the extract on. In kitchens any automatic control must provide sufficient flow during cooking with fossil fuel (e.g. gas) to avoid build-up of combustion products.

but does that not ignore the higher vent requirements for habitable rooms?
Table1 on page 14 shows general ventilation requirement twice the aquivalent area compared to kitchens. and no mention of extract ventilation.
Diagram 2 doesn't show such open plan mixed use unfortunately.

Is builder/architect just trying to fob us off? and how can we best respond. Other than getting different builder/architect...