Hi ,
I have used the toilet card a few times now ,the best response was from Tesco , there toilet was out of order so i aproached the customer desk and just showed the card from prostate UK and they took me straight to the staff toilet .
https://prostatecanceruk.org/prostate-information/our-publications/publications/urgent-toilet-card
also used the Radar key the toilets are usually in a better state that standard public toilets.
hope this helps .Regards Rpj