I know more than most about microlight accidents and their causes, and I'd say that in the public domain right now there is virtually nothing to tell us the cause of this tragedy.
Aftercasts suggest it's unlikely to be weather, and the fact that it's within the airfield boundary suggests it went wrong during either take-off or landing. The F2a used to have a bad reputation for mishandling due to mis-rigging, but that was all sorted out by research led mandatory modifications years ago and the type has an excellent track record over the last decade or more. Which basically tells us nothing.
I'd suggest that conjecture waits until there is some kind of evidence to be considered.
G