Can't say I know anything about that. Personally I'm using VFR Vol1 with
the
bundled terrain mesh so the London Scenery pack from Visual Flight seems
to
work just fine. Presumably the London Scenery pack was only produced with
VFR Vol1 and the bundled terrain mesh in mind. Perhaps it's worth asking
the
authors of "Terramesh" if they've got a similar scenery update available?

The Terramesh is much better than the supplied VFR mesh, except in this
instance, so it is annoying. Obviously switching meshes is the answer when
over London, but of course the scenery loading time is very long indeed, so
it's a drag :-(