I share your frustration with other writers' methods. For the moment, my best method does seem to be to sit in a pub and scribble away - the fact that other drinkers clearly think I'm an utter wanker reduces the temptation to daydream. Coffee shops do seem to be for people who want to be seen to be being creative - and in London they're so full of perspiring writers you can rarely get a seat anyway.

The drawback of course is that you eventually get too drunk to write anything decent, but this usually takes a couple of hours, and a couple of quality hours is a good daily goal for any writer with a full time job (or full-time children, in your case).

So, yes, try the pub method!