To be honest with you the handling agents at LGW generally recruit internally for traffic officer jobs so you would probably have to start on Check-in or loading.
The other thing with the traffic officers for Aviance or Servisair is that they are traffic officers and don’t really have any bearing on flight planning (Ops officers) or load planning (Load controller) unless they are the experienced ones on the US widebodies.
I don’t mean to put a downer on things but as it is one of the better jobs on an airport you've got a lot of competition
Good Luck
