And as I wrote on your other thread, particularly relevant to 195s -
You can't just fit a second toilet to a 195 without fairly major modifications.
I find it hard to comprehend how we've ended up in a situation where multiple units built over thirty years ago have more room to install toilet infrastructure than brand new trains.
Emergency toilet bags exist. Each train should perhaps have a stock of them which could be used in the toilet cubicle in emergency even if it had failed.
I've considered "bringing a bottle" just in case.