You coded it in six months and the whole project start to when you gave it up was only a year? Most startups I know of take several years to get any revenue at all. You need to have brass balls and a rich friend / family / side consulting to keep eating and paying rent / expenses.
You received 3000 GBP in startup money competitions, no strings attached, the first year. That's pretty damn good. I know startups that have raised a million dollars and don't have that much revenue.
Don't forget advertising. Sure you need lots of hits to make good revenue, but I know guys living off only ads for their apps. They also offer paid versions, but these tend to be a minority of the revenue. Don't underestimate what adsense/admob plus some social media exposure can get you.
You probably don't realize how successful you are already. That leads me to believe that if you stick to it, you're going to be quite successful. It may take 20 years, but eventually you're going to get some traction.
It's not the idea. It's not really even execution. It's persistence. If you keep trying your startup long enough, you'll eventually make enough to live. Maybe not be rich, maybe not make as much as you could have in a big corp (TM), but you'll survive, and you'll be your own boss.
My family has been doing startups for literally generations. I'm not rich, and neither are they, but we've survived. We did it by being persistent.
Stick with it, and I know you'll succeed. Don't give up.