Thanks @DP. The EVOhome system uses two separate BRD relays (HW/HTG) so it feels like I can include or remove that cable on 7(NC) in the HW BRD without affecting anything.
Hi - dramatic title but I'm fitting an Evohome HW and HTG smart thermostat/TRV/relay system.
When I traced all the wires to the programmer and beyond I found that the HW normally-closed pin in the programmer had a wire attached to it. It was linked to permanent Live and had a red sleeve on it...