How do I undo this?

[Nag4A]

I am in the process of replacing a concealed toilet cistern which up to this point has been totally inaccessible behind a plasterboard wall. I am replacing it and putting an access panel in place. Access to undo the water inlet connection to the cistern is very limited.



It is not entirely clear to me how I can undo this connection. My guess is that I have to undo the stopcock from the inside of the cistern first which will allow me to withtdraw the elbow that connects the water inlet pipe to the cistern at which point I can first remove the cistern and then do the rest. I'd much appreciate any help here.

 

[Geofd]

If your trying to disconnect the water from the toilet , first we need better pics, pic of the toilet would be great.
That 2nd pic of that brass nut...is that were your water connects to the toilet????? I would disconnect from there but I'm not sure if I'm answering your question properly

 

[Nag4A]

As a matter of fact you are. The trouble was not so much where to disconnect but how - the issue being the very limited access I had to the installation. In the end I reckoned that given the old cistern was destined for the skip anyway, I could simply be destructive. So I cut a square hole around the location of the water inlet to the cistern which allowed me to first get the cistern, partially, out of the way. With that done the nut was a whole lot more accessible and I managed to disconnect quite easily.

 

[Geofd]

That's a good ending!!!!!!