TDV8 Vogue Blowing Cold

Firstly, Hello Again!
To my shame ive been driving a X5 for a couple of years so not had many faults with my car. But now, the Land Rover Bug Bit me again and I picked up a 2008 tdv8 for towing my van. And I’m back in the not so easy world of Land Rover!
So my problem is, both my blowers in the car are blowing cold. I’ve done some investigation and water is circulating round the engine but not going through the heater matrix.all 3 houses into the bulkhead are cold.
So I removed them and flushed the matrix with no blockage.
Still cold, from what I can gather it looks like there is a secondary valve block on the passenger side mounted in the engine bay half way down the inner wing. If i try and flush water through this in way direction it doesn’t flow.
Has anyone ever come across this problem? Had to replace this? Or had similar problems with there’s?
Thanks I’m advance !

I guess that is ford/jag era so it might be similar to my jag s-type in that it has solenoid valves to control water flow to heater matrix. That said, on the jag when they fail, they fail hot.

As Wazzajnr said there is a valve block that stops working and stop the hot water circulating round the matrix.

Thanks I thought it might be something like that.
I’ve had a look I’m assuming it’s the block half way down the inner wing on the passenger side?