... the vast majority of those men who flocked to the colours in 1914 and in the years immediately afterwards considered themselves first and foremost British...
Very true. Unfortunately, and it is well documented, that this was not reciprocated. Indeed, the British generals often considered Australians and NZ to be 2nd rate citizens and fighters ... you get this impression when you read Breaker Morant, The Anzac Illusion and The Broken Years. Horatio Kitchener thought little of our diggers. I think, Wiley, Australians joined up and died because propaganda told them to do so. Just like we were told of the falling domino theory with Vietnam. Ho Chi Minh won and guess what? Thailand, Malaysia and Singapore are still tourist destinations with nite clubs and casinos.
If (and this is a big if) there was National Service today, I think you would agree with me that we would not be in Afghanistan, Iraq, and so on. Simply because, instead of sending our professional killers overseas you'd have a national conversation at the dinner table on the merits of us fighting for a piece of real estate (or worse, an obscure ideal of supporting Karzai) that has no meaning to our future or security.
But you are right about the gov of the day during WW1 not beng able to ignore the wars of Britain.