Found these on a Greek site,
Moto-Discovery. Inexpensive compared to the other reflective stripes I could find, VFR-specific and very rapid delivery. They don't quite fit as advertised in the instructions, they overlap when you get back round to the start, but it's easily fixed by reducing the distance between some of the sections. We'll see how they last an English winter.
Lots of other Cr bits on there too.
