Thanks for the tips guys. I should have probably mentioned that I break BMW's for a living so have a reasonable amount of technical knowledge but this had me scratching my head!

I have an X431 Launch diagnostic computer at work that I can get real time data on it but on the water temperature it wasn't showing me anything typically.

It's a very good computer on the BMW's but it's Land Rover module is lacking it seems because I couldn't see anyway of testing the speedo. I will check back though in case I missed something.

I also have a laser thermo checker thing that you can point at the water system and it all seemed to be around 80'ish degrees.

As for pixels on the speedo all is perfect which I realise is abnormal so maybe the temp gauge has been damaged during the fix process?

I have no way of knowing unfortunately what's gone on previously but I will certainly double check the water cap. I can compress the top hose fairly easily when it's hot but cannot hear any hissing and the water level is steady with no signs of leaks.

Unfortunately your BMW computer doesn't speak Land Rover, so while it will see most things engine, whether it understands is a different matter Land Rover did rather a good job of ensuring that only their computers would talk to the car.... they are supposed to be OBD II, but trust me they ain't

The only way around this is to get a Gap IID Tool, there are a few others out there that will do most things, but I have found that the Gap IID does just about everything, in fact I believe that it can do some things that the Land Rover SSD kit can't! But neither will switch the rear view camera type....... you need NavCoder for that  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

Just a little update to this. Had a good drive in it yesterday with plenty of traffic / A road blasting and it sat at 3/4 the whole time. I'm pretty sure following this that its a gauge fault now.

I still need to get round to double checking the pressure of the hoses but I will take a look at the rad cap and then report back if that alters the temperature.

If you brake BMW's then I don't think you'll have to look far to find a rad cap  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

Indeed

FYI my TD6 is running between 78 and 89 deg C when I'm not towing, and 81 to 105 when I am. Hope that gives you an idea of the temp yours should be at, the dash board will read normal from 70 all the way to 105, how much further it has to go before it says hot is any ones guess  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

If it's a pre-facelift car then you can use the secret dash menu to test the gauges and monitor the coolant temperature via the display.
The menu system is the same as you get on BMW's of the era so you might be familiar with it.

http://www.roverupgrades.com/Range_Rover_Hidden_menus.html

You want test 2 (gauges self test) and test 7 (Engine rpm/Coolant temp).