Bad luck on the heater hose but they can get brittle.
The stat housing will come out of the top but you need undo the two bolts holding the metal pipe to the front of the engine first.
There is then just enough room to move the pipes forward and disconnect.
The thermostat housing may put up a bit of a fight and can break off the stub and leave it in the block.
I think mine was cracked here anyway and the stub can be removed with a bit of patience.
Hope this helps and good luck.

Click image to enlarge

Good info, thank you! 2012 Vogue TDV8 in Aintree green

Mine also fell apart when the garage tried to remove it and then there was a parts shortage and they were not available......
The 3 bolts holding the thermostat insert housing needed the impact wrench to shift them and this was with the unit in parts and on the bench. All these 'ABS' black plastic parts on the coolant system are very fragile with age now and can snap if you just look at them the wrong way,
. 2012 TDV8 Vogue (L322)

Thanks also, JG.

I took a look yesterday as I finished my overtime job in good time. I cannot see a way to beat the workshop manual so the fan has to come off to gain access to the bolts to loosen the metal pipe. As a result I lost enthusiasm and decided to drink a few beers whilst watching the Revival.

I will regroup this week. 2012 Vogue TDV8 in Aintree green

Fan and shroud removal is a fairly big job but it then gives access to many replacable parts so it maybe time to think about some preventative maintenance and repace belts, idlers and tensioner, AC compressor, alternator and waterpump while you have the access. 2012 TDV8 Vogue (L322)

If you don’t want to take the shroud out, which is a pain, you can just undo the fan and move it in the shroud nearer the radiator. This will give a bit of extra room without taking the shroud out, just be careful not to damage the radiator. 2012 TDV8 4.4 Westminster Santorini black
2016 Discovery 4 Landmark
2002 Defender TD5

It can be done without moving the fan. The metal pipe will just move enough to allow the rubber part to come off. Which is just as well as I did not fancy working underneath to remove the bypass valve and cowl.

However, back ache and a difficult hose clamp stopped progress today. I am now searching for another tool for tricky spaces.

The tricky clamp is tucked away here. Pedro decided to turn it 90° at the factory to where I would like it:

Click image to enlarge

Click image to enlarge

Apart from the age related failure of the plastic becoming brittle the insert housing that holds the actual thermostat is a pretty weak design in itself so I could see how this could easily fail on a pattern part. 2012 TDV8 Vogue (L322)

The corner has been turned, albeit very slowly. The last stubborn hose that was holding up assembly is off, and the lower 'stat housing is on. Then it chucked it down. Weather forecast looks dry for Saturday.

Some more slow progress. I had a horrid cold last weekend so didn't do much and nothing to this.

Oil cooler on and new oil feed O rings fitted today. The old ones weren't leaking but were on their last legs.

I am now off to Bicester the for last Scramble of the year so I probably won't do anymore work on this until next week.

Good work, making good progress. Just had the oil cooler gaskets replaced on mine at the specialists... 2012 4.4 TDV8 AB Sumatara Black with Ivory / Jet interior

On the home stretch now and I am going to tempt fate by predicting an engine start tomorrow.

The keen-eyed among you will spot that the new doughnut hoses are shorter than OEM by 10mm. I have not tightened them yet.

I mailed the eBay seller but he said that it was measured off OEM but I suspect that is total . Anyway, I have left it too long to return so if they are too short, I'll have to write-off the £100 and buy a metre length and cut them myself. Lesson learned, don't take too long to fit parts if the seller's terms are 30 days.

Second, the middle hose to top hose in the upper thermostat housing is retained by a pretty feeble clip on the pattern part from Maltings. I wonder it if will hold when it is up to temperature. We shall see.

You originally had the upgraded OEM 4 intake hoses fitted, why not just put those back on?

There were signs of misting but yes, that is an option. 2012 Vogue TDV8 in Aintree green

The late OEM couplers are silicone so the will mist as they are slightly oil permeable. 2012 TDV8 Vogue (L322)