Hard brake pedal after rebuild ?

You can now see some of the thread where it starts on the rod, so I moved the nuts say 10mm

Or am I being really stupid and need to twist the actual rod itself

No just the nuts. You can feel a bit of a wiggle with your fingers when its backed off and not pushing on the M/C. Start there.

I am going to start from scratch, are you sure i don't need to have no pressure in the lines before doing this as it feels like there is tons of force on the rod and no free play wherever i move the nuts. Annoyingly my workshop is 10 miles away with no signal when im there so its a proper ball ache when i come across an issue. Also if i have trimmed part of every trailing shoe will they now have to be replaced as i have brought them out of round ?

Undo the bolts that hold in the master and see if that releases the pressure on the wheel cylinders. You need to make sure you can release all the pressure from the rod and then as I said you need to be able to feel a bit of free play when you adjust it up before it meets resistance from the M/C. If you can't do that then its probably the wrong master and/or rod.

Slacken both nuts with, let the pedal settle in up position screw the nut furthest away from the cylinder till it is nearly touching pedal assembly bring the other nut to similiar position, try your brakes,the ball end on the rod that sits in the cup of the master cylinder should not be in contact with the cup of master cylinder hence a small bit of freeplay to allow the master piston to come back to rest when you take your foot off the brake pedal.

Today i tried adjusting the nuts and couldnt find an area where there was any free play. Just solid pressure. Its almost like the nut needs to be able to screw further back. With the series 3 is there any differences in rod length/ the amount of rod thread within the cv and cb type master cylinder ?

This is the exact one i purchased

Whilst this one in comparison is threaded nearly all the way down

Been looking online and i have a horrible feeling i was sold the model suitable fir the LWB as all the swb models look different to what i have...

Very unusual to have a metal cover in place of rubber was it this one from Foundry 4x4 as it does say LWB in advert
https://www.ebay.co.uk/itm/Land-Rov...558214?hash=item56c93f5446:g:clcAAOSwlmxdXBdM
SWB version
https://www.ebay.co.uk/itm/Land-Rov...ithBBEV1Filter&_trksid=p2047675.c100005.m1851

Thanks for the responses guys, yes that is the exact one I mean I did pay 12.00 for it and the guy said it would fit. I have just ordered the bearmach one so it will be interesting to give them a side by side comparison. I get a horrible feeling I'm going to have to replace the shoes that I trimmed down too. Luckily they were only britpart and not mintex!

I think you got the wrong one in the first place.....
Never seen one with a metal cover either so don't know what that's for. Personally I've never had problems with Britpart shoes and others have had trouble with Mintex so its probably a lottery.

The two master cylinders are two different bores as well so definetely not compatable.Snip from manual attached

Interesting I think you are right and I have the wrong one, well I have ordered the replacement parts necessary so fingers crossed it will be a smooth day putting the new bits on and getting the brakes functioning.