Any thoughts on cause of death at this stage are premature and just speculation. There's too many variables to say it was the squall, or his age and fitness, or he got his lines wrapped around his legs. For sure 9 degrees water temp, his wetsuit, age, a 12m kite in a squall, how was his QR rigged, did he pull it, did he have a knife are all factors that probably come into play.
Most likely the factors that caused it will be identified and put into a report for the coroner (or their UK equivalent) and a reasonable account of what happened will be pieced together. The reports are not normally confidential but no-one ever puts an FOI request in to see the final version so we'll probably never know.
There's not much on the net about this one yet except someone on Kiteforum saying it was a 12m kite and not a 15 and all the online news regurgitating the same media release from the sea rescue guys (RNLI?).
Just found this thread,
kiteboarder.co.uk/kitesurfing/bad-news-hayling-64958?sid=e6bcbad3cf0d18d1c0ac8bd8f02e9318 Squalls gusting to 28-29 knots at the time, nasty on a big kite.