Despite being female, I had the exact same problem as you guys. I lived in a nice area in Liverpool, and was getting quotes for £5000-13,000 depending on the car. One thing that I decided to do was give up my ability to drive at night (11pm onwards) and I think it was with the company below, but apparently, they reduce your quotes by a HUGE amount if you don't drive from 11pm-5am. It may be worth checking it out, otherwise, I found that personally, the best comparison site is CONFUSED.COM and you are actually best getting a KA or something for a year. I passed a year ago, and didn't get a car, but am getting one this week, and my insurance quotes have gone down so much, despite having no driving experience. Also, I'd advise trying to call directline etc, as they may help, and I hear Endsleigh are also good for younger drivers (although for me, Admiral were the best, so I may call them up and haggle for a bit, and if that fails, just call again with my online quote).
I've heard that playing companies off on eachother is the best way, so pick up the phone and give it a go. A few companies like Diamond refused to give me any reductions, so try Elephant and any companies you know that may direct their quotes at younger drivers. But seriously, stick to a cheap car, it makes the world of difference.
When I moved to Sheffield for university, my quotes went down drastically too, so if you're going to university soon, that may be worth thinking about.
Good luck.