By the comments posted thus far, it's obvious no one knows how much traffic goes through this area.
Agree 100%!
More to the point, it's the "quality" of pilots flying through this area.
Back when I used to fly around there I considered anywhere south of the EN CTR right down to Cowes (including all around the bay and the MB Training area) to be a Danger area.
It's not just the quantity of traffic; it's "where they are" as pilots. You've got English challenged guys who are taught at the sausage factories going on PPL solo flights through there.
Some of these guys have almost zero situational awareness. Couple that with an inability to fly their areoplane in a practical way (i.e. if they're taught to fly over Brighton, that's the only place they'll fly over. It's not an option in their minds to fly 1nm west of Brighton and report "1Nm west of Brighton" when contacting MB tower).
And it's not just trainee pilots. I've seen countless examples of so-called experienced PPL's and CPL's who just barge on through there without any concept that other aircraft are in the sky.
IMHO, it's an accident waiting to happen.
DIVOSH!