Have you actually read Catriona Pennell's book "A United Kingdom" Keith.

No never Guest.
I did read her "A Kingdom United" a couple of years ago. Would you like me to dig it out?

Meanwhile, here is a review of it from The Times Higher Education Supplement,

"Pennell argues that historians of the UK have lagged behind historians of German and French history in reassessing the picture of "war fever". She seeks not to demolish the notion of Britain and Ireland as accepting the need for war, but rather to argue that the public's support for war against Germany was based on a reluctant, but rational, agreement that it was necessary. After an exhaustive search in primary sources, she concludes that "in reality, the responses of ordinary British and Irish people were much more complex than the myth of war enthusiasm would suggest...[they] did not back the war because they were deluded, brain-washed and naively duped into an idiotic bloodbath, as the subsequent myth would have it"."
https://www.timeshighereducation.com/books/a-kingdom-united-popular-responses-to-the-outbreak-of-the-first-world-war-in-britain-