No Dccv on this Jag.

Trosty you have the classic symptoms of a blocked heater core.

 

DCCV ?

Does this mean the dreaded heat core flush through to see if it clears it? Doesn't that involve taking off the whole dash?

Dagnabbit!!!

 

Dual Coolant Control Valve.

 

Yes you should try the heater core flush first but this is done from the engine bay.

Locate heater core supply and return pipes LHS engine bay which disappear into the firewall

Flush may not be successful since blockage can be sticky.

Heater core is accessed by just removing glove box I believe.

Search this forum for more info and confirmation.