This would be alright for units stabled at Allerton or Springs Branch, but the amount of outstabling in platforms at the likes of Southport, Wigan Wallgate, Salford Crescent, Manchester Victoria or even Liverpool Lime Street, where there are no refuelling facilities, particularly on Sundays (when I have seen 769s in all of these places) this is no mean feat.
That said, being electric depots, how much refuelling infrastructure exists at Allerton and Springs Branch and how often do 769s reach Newton Heath, where there of course is.