I don't but I have a RADAR key. I find it really useful to be able to access the disabled toilets without having to queue, especially as I live in a busy city with often long queues for the loos, especially with the time it can take to get there in the first place, especially as I also have mobility issues.
One issue I've come up against is in a chain coffee shop where, for the only toilet there, unless you have a RADAR key, you have to get the key from the counter to unlock the toilet door.
But this seems to override the lock from the inside. Trouble is, if they see that the key is there, they assume nobody is in the loo and give the key and I've had someone burst in on me, thankfully when I was decent, due to this.
I do find that quite often disabled loos aren't monitored to be kept very clean and tidy so always useful to have some hand gel/wipes and tissues available should they be needed.