I bought a one way bleed screw and started to fit it on an extension, but then decided to replace the entire diff with a Jag one.
Someone does make a kit for the Jag diff which is where I got the idea.
All I was going to do is to remove the bleed screw, fit a suitable size flexible hose instead, then run the hose to a bracket somewhere a lot more accessible perhaps even inside the boot somewhere safe, then a double ended adapter with the one way bleed screw.
I think Fosseway do the whole thing, pipe bleed screw and bracket. I planned to do it when I rebuilt the calipers and diff but I've yet to work out a position I'm happy with. Everywhere seems to have a down side...Needs to be hard line or any length will make the pedal spongy and hard line can be very noisy.
Current thinking is to have the nipple pointing upward at the back of the fuel tank, behind the cardboard panel. The bleeding tube can then do a U turn down into a bottle in the boot well so the fluid will run back into the bottle when you take the pipe off the nipple. Gotta empty the boot first...