So, I finally got sick of my dirty looking headlights.
It is quite common for cars imported from Japan to have very dirty headlights. Apparently it's caused by the smog eating into the surface of the lens.
I used a Micro-Mesh plastic polishing kit. I've used them quite a bit in my job as an aircraft engineer with good results, so thought I'd give it a go.
Here are the results.
Not a bad result. :-)