I don't have an answer but am interested in this too.

I met a GGL on a TATL a few months ago- very nice chap. He was an independent contractor/security consultant and ex-Police but flew a lot, paid for by his clients but like me also has his own OnBusiness account. We are both Tier 2 (that's £18k-£300k so it covers a VERY wide range). He told me he is 100% (well, within reason obviously) guaranteed to get a car from the C gates and indeed I witnessed this myself, much to my own green-eyed delight...! I think some of these people have notes beside their accounts that mean SS know they need to deal with them.

Hopefully one of our ambassadors CWS or Tobias-UK or orbitmic or golfmad or KARFA will see this thread and reply because I think they will have a good idea of the low-down. I am actually not sure if GGLfL commonly get SS treatment even though they have the highest possible CIV outside of PREM. From a business POV to BA they are probably not that important anymore (**runs for cover** ).