Lewis - I'm afraid I have no connections within airports for Heathrow / Southend but I just want to wish you all the best.
A few years back (Well more than a few!) I started off at HUY after having my work experience at the airport, I contacted the airport direct and explained my situation and was lucky enough to be accepted.
Had a great week and gave me a slight insight into the workings of an airport.
Hope all goes well and good luck