edit: ^ beat me to it.
I haven't seen anything to suggest the "rule of six" means you can't have six people from six different households in a group.
Its a simple rule now, but quite unbalanced towards allowing mates to meet up, but not families. As a family of four we now can't go and visit most families we are good friends with, as they are also families of four or more, yet I could go and get pissed up in a pub or someones house with 5 mates from all over the country.
The issue I suppose is that, allowing two family bubbles to meet up is harder to police than just anything over 6.
Selfishly, maxing it at 8 would have given us many more options for relatively safe socialising than the 6 you're allowed. It's a shame children of primary school age count towards the total, given the arguments that they don't appear to spread it anyway.
The possible benefit is that I may have to go for a nice solo bike ride / read my book with a beer while the rest of family meets up with some friends.