Allow user to turn off partial opening of thermostatic valves

The ability of the thermostatic valves to partially open allows the Tado system to better regulate temperature and avoid overshooting target temperatures. However there is an energy efficiency cost.

I live in an old house where many central heating pipes travel through unheated voids in the loft or under floorboards. If I have a single room calling for heat from the boiler whilst its valve is only partially open, all of those pipes will get red hot and leak heat, while the room gradually tiptoes towards its target temperature.

Given the current energy crisis, I would like to be able to switch this feature off, so that my valves are either fully open or closed. This would mean rooms would overheat on occasion (which wouldn't be a bad thing as our temperatures are on the low side of comfortable!). But our boiler would be on for less time and our pipes would spend less time leaking heat into the loft.