We'll have to wait for more information from AAIB so there is little point in speculating.
However, it would be a relief to some of us to rule out the involvement of friends and colleagues asap. It is now over 24 hours since the incident and we still don't know, officially, of the type involved. If the BMAA knew hours ago the type of the SEP involved, it seems odd that that the media is still peddling false stories.
In particular, there is a presumption amongst the Great British Public (as I found out at work today) that the Cessna 402 was automatically in the right because it was filled with experienced commercial pilots.
In the sport and recreational area we have to be careful not to be labelled as casual and dangerous playboys getting in the way of 'important' traffic
There is no doubt that something went wrong with look-out - be it visual or electronically assisted, and there, for the grace of God, go all of us. But in the meantime more facts are needed to make any judgements. These will emerge in time, so let's wait for them to appear.