Originally Posted by
IAMORGAN
Going forward, it sounds as though you should pre board and let the crew know that you need immediate access to a WC.
How could this be achieved? The only way would be to reserve one of the ever-decreasing WCs for disabled passengers (I apologise if that's a politically incorrect term, but you get my drift).
As C-W-S alluded to upthread, there are times when I think people have fallen asleep in the loo they spend so much time in there. So, even if the OP had been granted access to the J cabin, there's no guarantee that the WCs would have been available.