Snapshot answer
They’re seaside saunas made out of old horseboxes, which have become something of a craze. For £12.50 a pop, the Beach Box Spa in Brighton (pictured) will let you swelter at 110C for 45 minutes while someone gently beats you with birch branch whisks. Small sweatboxes are so popular that there are now around 50 of them from Cornwall to Aberdeen, with dozens more on the way.
The Knowledge
In a word ,NO.
Wow, wow, yes, yes, it sounds brilliant
No mention on their website of getting flogged with birch twigs though, thank goodness
I think that may be a flight if someones fantasy!
Are they by the beach so you can jump in the water after you’re done in the sauna?
Yes, they really are, that would be amazing. I’m looking into a trip!
Sounds great to me, including the flogging…Where can I join?
You’re overly interested in the flogging……
Will it be naked flogging?
Foxy, you are flogging a dead horse, in a dead Horse Box 
Why do the southerners have all the fun Spitty, I haven’t seen these horse boxes in Cleethorpes…
As a southerner I can think of much better ways of having fun…a list as long as my arm 
I should like to examine your list Chilli…
I bet you would!!!
My handwriting is appalling
That made me choke on my tea OGF.
Behave lol.
I’m a Londoner so I know nothing about what happens north of Chippenham, because it’s all Scotland after that
But these things do seem to be popping up all over the country, (saunas that is, not OGF and naked floggings)
Is York north enough? this place looks really nice
So ,do you want to be flogged or do the flogging or both?
Sitting in a horse box sauna at the beach gets a no from me …a beach hut 
There is a horse box (motor type) here on the beach serving coffee and snacks .
Is there a Horse peering out of the third box from the left, note the lack of a chimney.
There is someone in that third box !
Maybe a late 18th century child, who did not want to be conscripted into the chimney sweep trade. 
