He must have found it a difficult commute to Merchant Taylors (a day school)I really don't know what to make of that bio on Wikipedia....it is nothing like the story of his life that Jack gradually tells during the episodes of Out Of Town, where he makes it quite clear he grew up on a farm in Yorkshire, working amongst pigs and cattle and controlling heavy horses.
After attending an expensive and exclusive independent school both he and his brothers went to university in the 1920s when there was a very restricted entry (and it was relatively expensive), his father based himself in London 'for commercial advantage', not bad for 'a Yorkshire farmer's boy'. His mother apparently insisted he spend time on a friend's farm but it was in Bucks not Yorks. Out of Town wasn't broadcast up North (indeed for many years I couldn't understand why people kept going on about this Hargreaves chap) so maybe he thought he could get away with a bit of self-mythification (something media folk are prone to) and once started found it difficult to stop.