Then your error is not related to having loaded the wrong .INI, but possibly something else, please post a startup log at that airport, and possibly the .INI file you are using, which might have been loaded, but not correctly.
See attached below.
The only way currently to get GSX to recognise EGLL (Or any airport that doesnt have any stands showing) is to delete the .ini files in the appdata virtuali GSX folder, and any custom ini in the addon scenery folder, as highlighted below...But...This then leaves no animated jetways...GSX then beleived theyre all default and wont animate them...SODE then shows no objects nearby...
Also note, that all these CFGs in the image were not generated when I did a fresh install of GSX, even after regenerating airport cache, i had these backed up as they were already located in the folder before i did the update 3 weeks ago.
Another thing to note, the airport ini below doesnt have a path to the UK2000 EGLL scenery folder, like other UK2000 sceneries do.
I have also included EGKK and EGCC
EGKK Works fully for me, jetways move, i beleive all stands show.
EGCC Works partially, all stands show, but no animated jetways (SODE says there no triggerable objects within 12km)
The same at flytampa dubai, all gates work, no animated jetways, SODE says nothing there.
One thing I do find odd, is Taxi2Gate OTHH V2 works fully, absolutely no issues as of yet...but i cant find a single .ini for it.
Ive had to convert the .log to .txt files as the forum wouldn't let me upload it.