Well, looking at this one here, I would say he is right: Everything from Leeds upwards will be closed and I guarantee you, it'll get worse!
The latest London VAAC Ash concentration chart is a little more troubling and given the synoptic situation, one has to question as to whether the Southward extent of any ash concentration is being over-estimated.
What is your perogative for being certain of it getting worse?
I've posted the synoptic evolution for 0600 in the top right hand corner also. With that ridge of 1030MB pushing in from the Southwest rapidly during the day, any risk would diminish across Ireland relatively quickly and the bulk of Britain would likely remain clear, as Winds back Westerly. However, peripheral areas of Scandinavia could potentially be affected later by low-medium levels of ash contaminated air, mainly below FL200.
EI Premier