I'm walking into a lot of houses each week as a contractor. It is not always possible to be 1.5m away from people when working in close quarters. If we are in somebody's house for the purposes of "work" there are no restrictions on number of people that may attend. All of these new rules / laws were written on the fly and not fully thought out for all scenarios. There would be so may loopholes that could be exploited legally if you were busted in an outcall - all comes down to how public you want the debate to get.
You don't argue with the boys in blue until you are in front of a magistrate.