For Aerosofts Mega Airport London Heathrow.
The fixed AFX_EGLL.bgl file should land you more centrally on the runways at Mega Airport London Heathrow for FSX.
Rename your original to AFX_EGLL.bgx
Unzip the file and place AFX_EGLL.bgl file in the following folder.
*:\Program Files\Microsoft Games\Microsoft Flight Simulator X\Aerosoft\Mega Airport London Heathrow\scenery