Disco 1 warm heater

my heater only blows warm air out have checked the hoses to the matrix both the same temp warm,hoses near the thermostat are hot as hell and temp gauge sits just below half way not sure if its a thermostat issue,lazy water pump or the heater cores cloged up any pointers on this would be most welcome.300tdi

Matrix might need flushing but try bleeding the system first

You have an air-blending heater system and does not depend on the thermostat that is just to allow engine coolant to pass through the radiator. lazy water pump? Ive never heard of that.. so all that is left is a blocked heater matrix, air could restrict the flow through it or the dash controls are not operating the dampers but rare normally its just the one side that's having an issue with the control cable coming adrift..

OK thanks just had a go at bleeding the system have heard these are pigs to get the air out of what's the best way to do it?

Stat or water pump or both imo