you should also try Aviance or Sky Handling partner. at the moment SHP are looking for dispatchers(temporary basis i think).
SHP can be contacted via the Air France Ticket desk and Aviance by the BA desk
afaik.
from what i gather, these jobs are mostly offered in-house and as you mentioned you seem to have to start at the bottom rung which is where i am .... ground handling.
john.
oh yeah forgot to say, now is a good time to get a job on the ramp because summer is fast approaching ..... loads of aircraft not enough men!