I can understand your disappointment Mark but given the very low price of valve maybe to be expected. Having said that the four way electrically operated valve John V6 suggested in your other thread (linked below) is cheap enough to try your luck with. You would just need to confirm the hose unions work with the standard 16mm i/d heater hoses.

[Linked Image]

Hoses hopefully would swap straight over then a fused power feed operated by toggle switch added.

Richard

2018 Roadster 3.7
1966 Land Rover S2a 88
2024 Royal Enfield Guerrilla 450
1945 Guzzi Airone