Hi, like many others I too cant use London Landmarks. I thought it was a well known thing but I guess not. There are several posts on the flight sim forums from users who have had to uninstall the landmarks (like myself). I only checked (& signed up) to this forum today to see if there was an update yet, as I presumed you would be working on it.
The problem started with SU5 (or the first hotfix, I cant remember the exact one) but uninstalling London Landmarks then reinstalling it, solved it.. but since Hotfix 2 this doesn't work. MSFS stops at the loading screen every time.
London City airport is fine though.. it's just landmarks.
ps: I absolutely love GB Central! I cant wait for more parts of the UK
Regards
Steve