I don't know if this has been a recent fix but I was able to get the UK date format by going to Settings > Language & Region and choosing "English (United Kingdom)" as my language. Now in the overview they display as dd/mm/yy and when you click through it shows as number then month e.g. 6 May. It's still annoying that the formats are different in the overview to in the post (and both of those are different to summary blocks).