Were these unisex loos legal?

Yes, you're not getting it.

Males don't bleed from their vaginas and therefore do not require tampons. Both males and females urinate and therefore need equal access to such facilities. You cannot provide facilities that only males can use without providing facilities that are exclusively female, as you would be providing more facilities to males than females. Therefore you are discriminating against females, because females cannot stand to urinate.

@Don'tLikeCrumpets Morally wrong was what I meant.

For instance, this www.cheltenham.gov.uk/info/65/public_and_environmental_health/1347/toilets_in_commercial_premises
For a capacity of more than 16..

Hi Pyewhacket if the Op opens her web browser and searches the council name and premises licence Op can find the local requirements. Most councils require a floor plan marking toilets. Some dictate the count of female and male toilets as a ratio of customers.
Obviously tiny places might only have one, single use loo.

@bythere What do you mean by totally wrong? Do you mean the facts are wrong or do you mean unisex toilets are morally wrong?

[quote DontLikeCrumpets]@RobynMyEmployer Urinals at the PH theatre not segregated. Women have "no choice" but to pass men using urinals to reach the cubicles.[/quote]
Totallly wrong.

I've seen unisex toilets and a separate mens toilet in my local Tesco. It meant there were urinals to wee all over and toilet seats for men to wee all over. I won't use them again.

This is the problem. Male only provision is available without a similar female only provision, therefore there is discrimination on the basis of sex, as more services are being provided to males than to females.

@RobynMyEmployer Urinals at the PH theatre not segregated. Women have "no choice" but to pass men using urinals to reach the cubicles.

'Women need twice as many toilets as men, say public health experts' -
www.cnn.com/2019/05/23/health/rsph-toilet-report-scli-intl-gbr/index.html

fairplayforwomen.com/toilet-provision-in-the-uk/

www.gov.uk/government/consultations/toilet-provision-for-men-and-women-call-for-evidence/toilet-provision-for-men-and-women-call-for-evidence

Surely this area is segregated only due to the fact that men get their genitals out to urinate whilst women don't due to being unable to wee standing up and thus requiring a cubicle.

@Sofasogood1 You think that is as bad as it gets? Here's just a snip from a DM article about one woman's experience at the Playhouse Theatre. (I highly recommend reading the entire article)
snip

So it was with some horror that, earlier this month, I found myself in a West End theatre having quite the opposite experience.

That night, I was expecting to see Cabaret. I certainly didn't anticipate that, during the interval, I'd also be 'treated' to an impromptu performance of Privates on Parade.

But, thanks to the Playhouse Theatre's gender-neutral toilet policy, that's exactly what I got — front-row tickets to the unwelcome spectacle of a row of embarrassed men relieving themselves at urinals. Opera glasses were not required.

Why? There are no longer any Ladies' toilets at the Playhouse Theatre.

Facilities once reserved for women are labelled simply 'Toilets' and open to both sexes. The only other option are labelled 'Urinals'.

www.dailymail.co.uk/femail/article-10562439/Womens-privacy-flushed-away-Mother-says-erosion-treasured-sanctuary.html

Just found this on a website about building regulations:
As such, although they should provide separate facilities where possible, organisations are not required by law to provide single-sex facilities if the toilet is in a room (not a cubicle) with a lockable door

Can someone please point me to this clearly defined in law or guidance so I can write to these companies? I don't women's place letter quite makes that clear.

I was in the Science Museum recently - mixed sex loos with huge gaps at top and bottom of cubicles (like a couple of feet at the top) and shared basins. Would be interested to know if these were illegal!

They'd have to pass planning, building control regulations etc.

I'd be interested to know this too been to 2 activity centres recently that had two cubicles next to each other & were unisex. They had huge gaps around the bottom.

Unisex loos are perfectly legal. Loos like the one in your house, small cafes, or in bigger places marked with the wheelchair symbol. Not illegal.
Op isn’t describing a Unisex, single person, loo. Op is describing a multi-use mixed sex loo.

Unisex loos are not illegal, no.

This was a restaurant? The licensing authority would have requirements. It could cost them their alcohol or public entertainments licence.

Surely if the workplace laws apply to people visiting/burgling your home, surely they also apply to customers using toilets?