greetings simon,
we had them in the US as well back in the 70's. My scout masters wife had one.
I thought it was odd and wasted water. It connected to the hot water faucet, and the pressure drove the spray arm. You had to put it next to the sink, as it had a drain and the water poured out of it the entire wash time.
I think it had a rather large soap dispenser, so it lasted long enough to wash the dishes.
I never saw one in any store. When I asked where they got it, they called me weird. So I bragged about my moms Lady Kenmore dish washer with a butcher block top. Then they said, my family is strange, for having that, but no color TV set.
What ever.
My parents believed in books and parochial education, not watching much tv.