While my car is off the road I thought I'd investigate the weak heater output before it gets too hot to test it.

The heater in my Plus Four resolutely refuses to blow hot air until the engine has run for at least 5 minutes, and then only when at high revs. Allowing the engine to idle cuts the heat almost instantly; almost as if there is some valve redirecting coolant from the heater matrix elsewhere. Are other owners seeing similar properties? My dealer has helpfully explained that TADTS.

Engine coolant thermostat stuck open perhaps..?

The priority is to heat the engine when it is cold. The heater works well when the engine is warm.
I have the same thing on mine.

I would imagine this is down to the emission engineering ?

Most modern cars aim to get the engine up to temperature as quickly as possible so they can manage the emissions and during this phase it might be keeping the hot water within the engine loop? If the AirCon in a big BM is setup correctly it may supplement this to give you heat through an electric element?

Just boot it a bit more

My lower vents are useless. Blow little air ever.

I find my plus 6 very poor compared the trad heater.

MogCX
Yes I have exactly the same issue. I have raised it with my dealer while the car is still under warranty (just) so hopefully they can do something about it. Roger

Pre CX heater comparison.

20 year old 4/4 heater;
Driver’s left foot and lower leg roasting.
Passenger’s right foot and lower leg roasting.
All other parts of the body unaffected.
Bud
4/4 - Stanley

The first CX cars had wondeful air to the dash vents but no physical pipe connection to the footwells, they must have assumed air would find it's way down there, it didn't. The first fix was 3D printed parts to direct the air, that was better but definitety feeble even with the dash vents closed. I haven't felt any improvement on later cars so that seems to be as good as it gets.

Plus 6 has heated seats also - not sure if they were an option.