At some airports I don't get a full list of companies to pick for services, E.G Liverpool only offers me Easyjet and not Swissport etc.
You are not supposed to always get a list of companies to choose. The list appears ONLY if, on a specific airport, on a specific parking, there are more than once choice with an equal score.
If there's only one operator with an higher score than all the others, there's obviously no need for a menu, since the program already knows what to do. That parking probably didn't had codes for all the operators that have a score in that airport.
Of course, with the latest GSX version, you can easily check AND override the parkings codes defined in the scenery.
Also when I picked Easyjet it had Easyjet stairs bit Air China catering trucks ?
The ground operators and the catering operators are separate.
