If I'm not mistaken, BSP pipework is still (or was) used on the continent. I have been in many toilet blocks on camp sites on the continent where one sees 1/2" & 3/4" BSP fittings, especially outside water taps.
What's the point of ULEZ? If your vehicle doesn't comply, you pay £12-50, then add more pollutant, so therefore ULEZ is pointless - more money for government money grabbers. If your vehicle doesn't comply, it should be NO GO!:mad: