horstmann c17

Intending to replace elderly in-laws boiler Horstmann C17 timer with a Hive wireless thermostat but confused by the existing wiring. The boiler is a Biasi Riva OV but has a strange setup in that it has no external thermostat and a manual heating/hot water diverter valve (Servowarm valve). Due...

I bought a HIVE installation kit, and have spent several hours today trying to work out how the wiring should go within the receiver. The closest I found was here: https://www.diynot.com/diy/threads/horstmann-to-hive-wiring-check-please.476261/ but it's not completely the same. I have a room...