Freelander V6 gasket failure?

Hi,
My freelander V6 has the management light on all the time.
if i drive for 1/4 mile it starts to flash and have very reduced power.
the exhaust system overheats to the point of burning smell outside car.
the top hose to rad pressurizes quite quick but temp stays normal.
no oil in water,no mayo in oil, not using water at all. Bit of bubbling in expansion tank but not venting at cap that i can tell. If i let car tick over for a while thermostat opens and circulates ok. cabin heater gets hot ok.
Is this a gasket problem through combustion or is there a plug/leads problem somewhere. Any help or thought appreciated.

Doesn't sound like a head gasket failure.
Which light is on?
The one in the rev. counter means an emissions fault.
The one below the speedo will only allow you to run at reduced power. You will need a diagnostics check probably at a main dealer to fix either fault.