My problem with the milk going off was when it got delivered after I had gone to work, not because I had a lay in.I've noticed the change to diesel vans in SE England and London but the milko with the traditional electric van is still thriving here. I was surprised to still see them but they remain popular.. There's a lot of people who have an "early to bed, early to rise" lifestyle round here and a cold wind from the North Sea even in high summer so I expect the milk doesn't get much time to go off..
Ironically many of those people are getting up early to commute to London!