I knew I should not have touched it..... I knew !!!
but I could not resist as it is leaking and I have a new one ready to go.
I tried multi grips and thought it was unscrewing but it was the top part only.
I can get a small spanner on it, bugger all room and can't move it......

So long story short, I can't undo this thing, can't drive the car until I do and Sunday I'm meant to go to a car show....
hoping to not cancel...

So I'm thinking of trying to break off the top part to get more room..wise?
I'm worried thing to hammer the spanner might break the whole bracket and the would be a major.

Next is unscrew the bracket but there are oil lines connected.... might be the best option ?

 

Tried again....18mm spanner, I can move it a few degrees so I pushed the spanner carefully with a piece of wood and it cam un done.
I'm scared to try the pressure switch... I don't want to push my luck...

What do you think.. push my luck?
Very pleased it has been leaking a while and I've been worried it would leak real bad...

 

Duke
I my view, you can only safely undo the two senders by removing the capstan and its stand, then you have room to:
(a) support the casting tower against the undoing torque of the spanner you use to undo the senders. A pair of grips is fine placed on the tower as close to the sender a you can; and
(b) room to get a spanner on the hex without difficulty.
If your warning light sender is not leaking, leave well alone. If it is, replace it, but only as described above!
It is incredibly dangerous to try to undo them without counter-torque support on the tower. If it snaps off you are in a whole world of pain.
Also I advise NOT trying to undo the tower from the oil lines etc.

 

Thanks Greg, I am thanking the Jag Gods for not turning this in to a nightmare.
Very lucky it came undone.

My guess is not to much torque needed when putting the new one on, it has a new copper washer, so just nip it up!
Warning light is not leaking - I will leave that alone.

It has been leaking for a while and there is oil down that back of the engine, it will be good to clean this up and reduce the oil leaks.

 

The ROM I have does not specify a torque. A copper crush washer does need to crush SOME to seal. Finger tight then about a quarter turn. Somewhere in the region of 40 in.lbs I'd guess. This is just a guess however. As long as it doesn't leak when hot.

 

I can confirm that the new oil pressure sender worked perfectly, interesting to see the difference on the dash - the oil pressure moved around a lot more than the old one.
The oil pressure drops quite low when not accelerating.
Very cool...

 

The sender will come out with a crow's foot the first time and should come off with a stubby thereafter. Be very wary about hand-starting the things because I have received senders with wrong threads more than once.

For NPT and a copper crush washer I think the spec for torque is something like contact/finger tight plus 90 degrees.

 

I always just grabbed the pressure switch with a locking pliers and bent it back and forth until the head snapped off.
Then a straight socket will remove the threaded part easily.