I'm probably going to regret posting this but I'm not that concerned, well, I'm not concerned to the point where I'm happy to wait until 4 for the details.
I think there has been a lot of confusion about what a "social gathering" is. The short version is that it's not like a.. congregation of people in a given area. Here's the definition of the law:
https://www.legislation.gov.uk/uksi/2020/684/regulation/5
As far as I can tell previously the guidelines were no "social gatherings" of more then 6 people (and bubbles, households..etc) - but the police only had powers to enforce dispersal of social gatherings of more then 30 people. The law is being changed to put police powers in line with the guidelines, so I guess the 6 person (bubble, household..i don't know!) is no longer a "guideline" but something that can be enforced by the police.
What this means in practice: If you meet up with friends in the park, or garden, you weren't really supposed to do so in a group of more then 6. but the police were powerless to do anything about it unless there was more then 30 of you. Now they have the power to do so.
Likewise, you can go the pub, or for the sake of it, a skirmish site. But that isn't a "social gathering". Its lots of social gatherings, in the same place. This article has someone from BEIS explaining it:
https://www.morningadvertiser.co.uk/Article/2020/06/26/Do-pubs-have-to-limit-numbers-to-30-people
I assume the same is for airsoft.
People may ask "why can't I meet up with more then 5 other people in the park, but I can go to the pub/airsoft/gym/etc?" The answer from the government (not necessarily scientific) is that because the latter are, or at least, should be "covid secure", in a way that say your garden bbq isn't (again, just technically speaking, I'm sure people have had bbqs that would be considered to be "covid secure" if whichever h&s bod came round to check)
As ever just my assumptions/thoughts. I'll wait until 4. I'm very aware by typing this out i've jinxed it and airsoft is banned for ever but we will see.
edit: a take from Andy at UCAP:
https://www.facebook.com/groups/UCAPAirsoft/permalink/10160454182945031/