The entertainment industry is the hardest to break. As far as journalism/media goes, you're on your own and it's a really hard egg to break. I've been stuck in a dead-end helpdesk job for 4 years since leaving Uni due to personal circumstance, while carrying a film/media degree. Basically, to make it in this field you need to work almost three times as hard as others, maybe even become self-employed as a freelance - whether that be writing, reviewing, or part of a crew. To do so, however, you need stability behind you. For example, you've got the fact you still live with parents there. I have a mortgage and bills to pay, which has all but shattered my dreams and all I've worked for so far.
Don't give up, is all I'll say. Network, network, network - talk to anyone and everyone. Attend premieres and festivals in and around London. You NEED to do this.