If the ticket blew off whilst you were driving, it could well have blown off before you even saw it.
Seeing as 2months have elapsed since the offence was committed, you could just sit-back and see what happens. The worst seems to be that you will end up with a £70. fine instead of the £35 for payment within 14 days. I doubt that the Council will engage Bailiffs without first notifying you of the outstanding payment. Furthermore, there is always the possibility that the matter will be completely overlooked ; as is sometimes the case.
About 5yrs ago friend of mine was sent a Fine for speeding and completely ignored it and heard nothing further on the matter.(Too late now because my friend died 4weeks ago)
Ron.