I was about to change the flush and inlet valve in the cistern and came across this old old fill valve under the cistern. I can see the retaining nut but that’s it. What on earth is the rubber stuff around the valve just under the cistern and why would anyone do that? Leaking valve? There’s no leak and hasn’t been since I moved in 8months ago. One photo is the ideal look for a valve, the other one is mine.
Looks like loads of silicon smothered over the fittings...that's the polite version! Remove and start again
Probably have to replace a lot of that pipe. You could also consider a 90 degree isolating valve (same as in lower photo, except 90 degree), - or a copper to copper isolating valve on pipe where it travels up the wall and then go from there. Remove all paint where you need to do compression joint