Yes, the book publishing business is based there, but if you can create something of value then your accent, background or postcode should not matter (though it is worth noting that a disproportionate quota of Oxbridge graduates still hold editorial positions). But still, what matters is the work and the person who creates it, rather than their post-code.
The best advice I can offer – and all advice where creative writing is concerned should be taken with a generous pinch of salt, for really there are no rules when it comes to the human imagination letting fly – is find peace. Find a space and occupy it. Fix onto a routine. Make room in your life for writing. To do this sacrifices will need to be made, whether economic, geographic or alcoholic. But that’s OK. Because if the will is there, you will find a way.
Only when I stopped hanging around in pubs did I feel I was beginning to get productive and only when I relocated to my native North after twelve (largely memorable, often exciting, frequently exhausting) years in London did my fiction writing get anywhere approaching what I hoped it could be. So celebrate where you’re from. Everywhere has a story worth telling – every suburban street, every shopping precinct, every sea-front promenade. Step outside where it is you live, study or work and try and see it anew. Sometimes travel can help with this, so do try and see as much of the world as possible. Viewed from three thousand miles away Newcastle or Sunderland, Durham or Redcar can suddenly seem like strange, exotic places.