Manchester's had a "no visitors" to houses/gardens since the end of July. It hasn't brought infection rates down, (though maybe it reduced the growth rate). Certainly it didn't offer the quick tap on the brakes that people were hoping for. Sustainability of measures is a massive issue now, and I think part of the reason why Manchester is seemingly misbehaving so badly is that the no visitors rule isn't viable for very long.
People coped in the initial phase, but as weeks turn to months, the Dominic-Cummings School of "I'm using my best judgment" - as a parent, or as someone with older or vulnerable relatives who need support, or just as someone living alone and who starts to find it stifling. Personally I liked the simplicity of the 6-person rule, I just think the simplicity arrived too late to become a routine. Worst still there's a big chunk of the country where different rules were already in play, and it just sounds like another irrelevance.
I now think we're at the point where too many people are looking for loopholes, or they're resigned to extra restrictions and are making hay while the sun shines. I also worry that as the rules intensify (and so do the fines etc) we'll actually see people becoming more hesitant about answering the contact tracer's questions, or even to get tested, which won't help anyone. I know people are demanding restrictions but you only have to look at the restrictions that are already in place to know that compliance with rules matters, and for that people have to find the rules easy to follow over months.