Every outing (and there were many) had to be organised like a military campaign. However, if there was a Marks & Spencer store in an area, we knew that we were safe to sally forth. All we had to do was ask the supervisor, and we were escorted to clean and accessible facilities.
The pain and the discomfort came in stores (and other venues) where toilets for disabled people were advertised; many of them could have been classed as being in breach of the Trades Descriptions Act - money wasted on useless and ill-thought-out adaptations, or worse, very little spent.
One large hotel chain I visited last year had only two specific adaptations: a wide doorway, and the disabled sticker on the door. My mother said they were toilets to make you disabled.
There is no excuse for this. Superb design guides are available from the Centre for Accessible Environments, many other organisations can advise and, dare I suggest, how about some consumer testing?