ASTRA G 1998 S611KRK. No hot air, control knobs & linkages seem OK, checked both coolant hoses from engine to heater matrix and they're definitely hot. Suspect Heater Control Valve Vauxhall part 90566947. So far removed glove box & storage box. Haines manual doesn't cover this fault specifically but does tell me how to remove heater matrix. So if I remove centre console is the heater control valve accessible, or do I have to actually remove the matrix as well which would entail draining system? Is there anything else I need to remove to access the heater control valve?