I've bought a magnetic stick on tax disc holder from the RNLI. I was over in france at Le Touquet earlier in the year and it was a challenge to keep the ticket on the inside of the windscreen. Hence the magnetic holder.
Just put the ticket in the holder and it won't blow away.
http://www.rnlishop.org.uk/outdoors/motoring/info/magnetic-tax-disc-holder/513042.html
