jerboy....
The amount of gold and premier cardholders in JER is irrelevant to the continuation of a service - just look at JER-LHR. BA dropped that pretty smartish, and i don't think for a second that these frequent fliers prefer LGW....
BA might well remain committed to LGW, i doubt it though. They had the opportunity to expand there recently with the acquisition of GB routes but didn't opting to drop a few routes to make space instead. And there were plenty of slots & a/c available to do so if they wished.
With the demise of the BA regions, the end of franchises, the opening of T5, the beginnings of an ambitious point to point operation (open skies), the movement of long haul services to LHR, where do you see LGW fitting in? 90% of its operation is short haul that is a long way from profitability...
JER-LGW by easy by next summer.... watch this space