I know this doesn’t solve the route cause but I have a solution to share. When lockdown got lifted there were no toilets so finding somewhere was a pain. So I bought the wife a She wee and I bought a portable urinal, which compacts down and upto 750ml.
Used in emergencies, the wife can use the she wee straight into the urinal etc.
With a little practice you can go in the car, discreetly etc.