I dont mean working for the airport or an airline, but for like the WH Smith or whatever in the departure lounge. How would I go about applying for a job at the airport, as alot of the places are past passport control arent they?
You could look on company websites (e.g. Dixons, etc. which are often through passport control recruit online I think). You could also try going to the airport and asking at a general information desk to see if they have any information on job vacancies. I'm pretty sure I saw a recruitment board at Edinburgh airport when I was there once with details of all the vacancies they had for general airport staff, as well as shop workers.
Ring round the individual companies, for WHSmith you need an application form which you can get from any WHS store. You also need a disclosure (criminal record check) but most companies will pay the fee for this for you, and they also need up to date references covering the past five years so you can get a security pass to enable you to work at the airport.