Odd One,
The trial doing the same with fixed wing last year failed and hasn't been repeated. You'll probably get a routing far enough away from the aerodrome to make the experience not very interesting.
Your information is incorrect.
Bar the usual caveats about subject to traffic etc, there's no restriction on light fixed wing a/c transitting Gatwick via the overhead (or technically most likely via the threshold of the runway in use).
I've recently both flown it in an a/c and cleared people to fly it whilst sat in front of the radar, so hopefully I've got a rough idea of what I'm talking about
WF.