There is an OH plugin for evohome - Either through PaperUI or there is a newer version tracked here
As for controlling the valves, you can, through OH, set the setpoint of a room. It then tells evohome controller and the evohome controller tells the TRVs for that room.
Advantage is you don’t have to track the temp and turn them off. It feathers them to maintain the temp.
Thread above has lots of information around how to use them too.
Many places to buy them from, I buy from these guys: https://theevohomeshop.co.uk
C