Changelog:
Version 1.06

Fixed glitch between track and kerb exiting Goddards
Checked entire track for similar problems and fixed where necessary
Initial release of National Circuit.

Version 1.05

Fixed problem near pit exit which caused collisions for cars with very low ground clearance
Tweaked shaders for less contrast between ambient and direct light
Added much more trackside detail

Version 1.04

Increased pit places to 24 which should allow a full grid in multiplayer*
Textured remaining buildings
Made cones and corner markers physics objects
Optimised resolution and bit depth of textures where appropriate
Improved models for all tyre barriers
Added trackside objects, vehicles and marshals etc.
Added LOD settings for performance improvements

Version 1.03

Fixed the pitlane issue so people running with penalties enabled won’t be limited to 50kph
Changed the sectors so they’re distributed more evenly around the track. Can’t remember where I got the locations for the original ones but think they may have been for the National circuit. Also made sure the objects for the splits (and start/finish line) are outside the track boundaries so it should no longer be possible to miss them.
Added a background/horizon object and texture. Looks much better for it, although it probably needs tweaking cos it looks a bit too mountainous from some replay cameras.