After a pair for my up and coming Sva
Might be worth checking out your local caravan accessory shop for some?
Large Tesco Extras have them in the towing section!
My car would have failed SVA at Gillingham with stick on ones, tester said they didn't have a high enough reflectance level. He did let me go and get some others and even directed me to the local caravan spares stock place.
I used stick on ones (have to be retro-reflective) that I got from a carravan shop. Think they were E-marked but they didn't check.
adrian