I am told that there is a City & Guilds qualification available in Airfield safety management, and most large operators are now looking at it as a minimum enrty requirment.
As for Manchester, there are sometimes external vacancies, but in the main they like you to have some experience of the airfield
My advice is to download CAP642 and CAP168 from the CAA website (both free) and digest them totally, this will stand you in very good stead. Then try some of the smaller places like Liverpool, Humberside etc before looking to move onto a bigger field like MAN.
Hope this helps and good luck