Alright, this is what I got, @richboy2307. FPS were again pretty good en route, started dropping into the 30s in the Brussels area but remained relatively steady.
It was when we started dropping into the 20s and then once again into the teens - all the way down to 12 - when we started our approach into Luton (screenshot attached). I attempted to remedy this by dropping my graphics detail down to the Medium preset, but that did very little.
There's just something really bad about the terrain rendering in this part of the globe, because, again, I'm just running the autogen EGLL airport - not the ini EGLL one or the Asobo handcrafted one - and the only other 3rd party scenery I have enabled in this area is ini Stanstead. The handcrafted one from Asobo is turned off.