To raise this with the office manager?

[Tempnamechange5]

I work in an open plan shared office which currently has about 10 different companies working from here.

I've noticed recently that more and more people are using the accessible toilets. I do occasionally need to use this facility due to medical reasons but more often than not I can use the ladies toilets. I was chatting to the cleaner and she told me it's because people find the main toilets too small and prefer the space in the accessible ones. While this is a bit frustrating I obviously don't know if this is true or a cover story someone has told to not have to explain why they need access to the facility.

So this week I have also noticed that people have started using the accessible loo to take private/personal phone calls as well.
We do have 2 meeting rooms and a separate kitchen so I suppose these must all be full if people are doing this. Usually people step outside on the patio to take these sorts of calls but it is very cold so perhaps this is why?
Anyway, so today I really needed to use the accessible loo and I couldn't because 'Joe', the MD of one of the other companies was in there on a call (saw him go in and could hear talking sounds through the door). He came out about 5 mins later, still one the phone but wrapping up, hadn't flushed or used the hand dryer which suggests he just went in there to take a phone call.

I do know about invisible disabilities, I have one. I am very accepting of this. But this feels like a piss take.
Part of me wants to raise this with someone but part of me is also doubting whether I'm BU as perhaps he does have a legit reason to be in that space and just happens to be on his phone...

I would just be very upfront and honest and say something like "I appreciate that people like to use the accessible toilets for various reasons but, occasionally I need them over the ladies for a medical reason so if people could avoid taking calls in them then I'd appreciate it". It'll depend on your work set up whether it'd be best said to a higher-up to pass on or via email to everyone etc.

Either that or sneak in early and put up a sign on the door saying 'due to GDPR liabilities and on-going litigation, phone calls must strictly not be taken in the bathrooms". People will be confused but are unlikely to disobey the written word and the ever-threatening GDPR.

is there someone who is the building manager? you could email them and point out that you have found the disabled toilet not accessible because of phone calls. That person could email everyone / make a sign / enforce the rules.

I have ibs and awful periods so I get the need to go quickly but I'd be wary of raising this as a single instance as many people just don't understand. Five minutes isn't terribly long and it's not the sole toilet available.

Maybe keep record so your complaint has mour clout?

There is an office manager who owns the building (or is a shareholder or something, I'm not entirely sure as I don't have anything to do with the building's company) but she also uses the accessible loo to get changed in.
Since we all work for different companies, there isn't really a 'higher up' to speak to other than her

This, I have arthritis and thought you wouldn’t know it to look at me sometimes need to use the rail to pull myself up in the accessible toilet. However my colleagues assume ‘no one here is disabled’ so just use it as it’s roomier. I get on well with our lovely building manager so asked him to send an email round not naming anyone but reminding others not to use the disabled loo if they don’t need to as it prevents those who really need it from using it.

The problem is, as you say yourself, you don't know that other people don't have a genuine need, even if it seems they're taking the piss.
Have there been any occasions when someone you know for a fact needs the accessible one hasn't been able to?
Don't put a sign up about GDPR. You'd be (quite rightly) laughed at. (What would be a contravention of privacy (though obviously not GDPR) is asking why somebody needs that toilet!)
I'd take the cleaner with a pinch of salt as her answer to your question was presumably what she thought you wanted to hear.
The only thing really would be to ask building management to issue a reminder about the use. But nobody is obliged to state why they need to use an accessible toilet.

No it's not the only toilet available but it is the only one with direct access to a sink which is what I need. The others don't have a sink in the actual cubicle.

Yes, often it's me who can't use the accessible toilet when I need to.

In this instance I know he wasn't using the toilet as he went in talking on the phone, never flushed or turned on the taps or used the hand dryer and there wasn't any bodily fluids in the toilet bowl. I had to wait outside hoping he'd leave soon so I could get in so the 5 minutes felt like a life time.

I know no one has any right to know why someone may need to use that space, I myself have been questioned in public when I've been seen leaving one because you wouldn't know to look at me. But the sudden increase in people using it despite the people not having changed makes me suspicious.