Yes I can confirm this issue, I had the same experience / behavier on Friday last week and this is the cause why I registered me in this Forum here. I reinstalled my last HOtfixed
I had a Teamviewer session with the OP samwheeler, which had this crash after a few seconds when loading P3D.
It turned out to be GSX didn't had anything to do in this case, it's was a problem with FSUIPC crashing on start, which is known to Pete Dowson. As soon we removed it from startup, P3D loaded normally, with GSX and several other modules.
If you know how to disable FSUIPC from your DLL.XML file, you can try that and see if it fixes the problem. If it doesn't contact me in private to arrange a Teamviewer session, so we can see what's the problem in your case.