Nige, nope not flying I'm on A/L for a week wife and daughter on route to USA (well above ash) so Yes I do have some time on my hands as all the decent "Frankie Vaughan" web cam sites are shut till later tonight
But that aside we are in the "red area" so safe to fly as long as precautions are taken etc, but if we were in the "black area" we would not be flying.
Not difficult to work out and also not difficult to find the info
Met Office: Icelandic volcano - Ash concentration charts
But hey re CRM take a look at this and then answer the question which one is right