777
When I did work experience I was just 15. I wrote to pretty much all airlines/aviation companies around Aberdeen airport explaining I wanted a career in aviation and was looking for a work experience placement. I took up the first offer as they were coming in slow! I ended up with Business Air (now midland commuter) and did days in ops, dispatch, pax services, engineering, jump seating etc etc.. A few months later they called me up asking me to work on Saturdays doing odd jobs in ops and down on the aircraft -brilliant, lasted for 9 minths before they needed someone full time, and I was jut about to do my standard grades (GCSE's!)-gutted!
So as said above, just write a load of letters, and send them off ASAP, and good luck!
Sim