Posh bosh?

We're still  prepping the refugee family's house in the run up to their arrival at the end of the month. It's in a terraced back street, probably early 20thC in date. Out the back (see extra) there's a row of three little sheds: a coal hole, a ty bach (little house = privy) as was, and a wash-house  This last still has an old sink, disconnected now, and even an old pair of laundry tongs. We moved all the hazardous items (paint, toxic products and fish hooks) into the end shed which will be kept locked, with the idea that the first outhouse can be a play area for the children.

This is a typical old-style sink, usually served by just a single cold water tap. It suddenly came back to me that we used to call this 'the bosh'. It's a dialect word belonging to the lingo, known as Wenglish, chiefly of industrial South Wales (not far from where I grew up, as the buzzard flies). Not Welsh itself although using Welsh words and syntax, as well as an admixture of slang and expressions brought in by Irish folk and other incomers who came to work in the coal and steel industries.
Posh it's not.

(I wonder what our incomers will call this?)