The rules/guidance is actually VERY clear. Just look on the Gov.uk website. All written in plain simple English, bullet points, etc.
Trouble is that the media reporting of the entire Covid crisis has been utterly abysmal. Whenever there's a change in guidance, rather than clearly reporting the change, they gloss over it and go straight into a Boris criticism mode. Just look at Kuensberg and Peston at the daily briefings. The officials made announcements, the journalist questions SHOULD have been about the announcements, seeking clarity etc., but Kuensberg and Peston would always make some stupid question about things that happened weeks/months ago, just so that they could get a quote for their evening news segment.
Right at the beginning, businesses closed because they thought they had to after watching the TV news. People stopped going out because they didn't think they were "key" or "essential" workers. If they'd looked at the Gov.uk website for the facts, they'd have seen that the media reporting was wrong. The same has happened time and time again ever since.
And I hate to break it to the Cummings haters, but he was right all along. Moving for childcare reasons was always allowed as per Gov.uk website guidance. Just because the media reported it wrongly when that guidance was announced, doesn't mean it didn't exist. It wasn't some obscure loophole that the lefties tried to claim - it was clearly written in black and white on the website.
Perhaps people need to start learning how to research things for themselves rather than relying on the media, Twatter and Facecloth and relying on it being correct (it usually isn't!).