Doing some digging as I really want to understand the purpose of these lamp washers on UK cars, today...
So DfT says this about HIDs (and others of this type): "once fitted to the vehicle it must have headlamp cleaning"
What's strange is HID is not covered in the "The Road Vehicle Lighting Regulations 1989" and are technically not permitted but because of EU (under ECE Regulation 98) and new cars having HIDs, DfT has to accept these new vehicles and have made an exception for aftermarket HIDs. As long as they meet certain criteria. But they say you can't convert an existing halogen headlamp unit and replace with an approved unit only. Although I have heard of kits...no idea how this works then.
As far as I know MK4's didn't come with HIDs, and Euro spec didn't come with the washers.
So I'm still not sure what legal purpose they serve, or served back in 1993 and especially if they don't work for cleaning anymore.
What about JDM Supra's or any other vehicle with out washers, how can they be allowed to use HIDs if they have no washer?
Mat did mention if it's over a certain brightness they are required...but how often do you even see headlamp washers like this, the ones you see are flush and don't obstruct the head light...their purpose is to clean the lens.