Appreciate the link, AGA, but mine seems to 'hang' on 20 April at the moment. Certainly the route KEF-LGW looks like a challenge up to then
It is of note that in ground terms the deposits of ash particles in the south of England (Aviate 1138's 'pollen') did not amount to any more than a good dose of summer Saharan sand, if that enables a sensible comparison of risk?