Solved - I think!

OK I think it's sorted! Just to clarify, the picture I posted was actually just one nicked from elsewhere to show my alarm! My actual reading only got to 63 at its highest and stayed around 30 most of the time. Since posting the wind has dropped to nothing and the reading dropped to 0 and hasn't risen at all so I am thinking it was someone elses fumes!

If my blog goes very quiet from here on - you'll know I was wrong!

I'm publishing this as a separate post as my computer is shut down and for some strange reason my PDA won't let me post comments!