CoyoteOldMan Thanks for explaining and sorry about your roof! I actually thought it might be something along those lines, but as I tell my children - you get no points for thinking the right answer and keeping silent!
I didn’t get a whole set, just the 180mm one (thought it might be a good compromise, though not very helpful if I need a different size). It was £36 on the deal yesterday, so couldn’t resist. Today it’s gone back up to £65, so for once I have managed to run after a taxi (though for the full price you get it in 5 days, not 5 weeks. Don’t ask me why).
