Hi,
I read through your posts and I understand and very clearly remember going through the difficulties you are currently having. As a result, I learned early on a few ways to enjoy a hobby or two with little or no money, it can be really hard to make a few dollars when you're not "Legal working age" it's mostly to do with labor laws and of course paying taxes. Anyway, you mentioned that where you live isn't a really safe area, so doing things like collecting cans and copper wire and taking them to be recycled may not work out where you're at, but what about doing house work or yard work for family members or retired folks? After a certain age it gets difficult to do a lot of things around the house and having a helper around even for just a few hours a week a lot of the time is all some people need. It also might be helpful for you to get in touch with your local RC modeler's club and just meet the gang and express your interests in flying. At least in my own experience I found a whole lot of help and some of the guys that have been flying for decades have just offered or given me things that I needed simply to keep my interest. You might even find that there's a few people in the club that could use an extra set of hands around the house on the weekends.
I'd say it's a good idea to get started with finding a club close to where you live. Get on google and just search for RC modeler's clubs in London, or more specific possibly, I have no idea how big London is. Contact the club by email and ask about getting involved and coming out to visit the site. Most clubs are just fine with the general public and non members coming out to visit their sites. The first time I went out to my local site as simply a person with an interest in flying but no experience flying, I was given my first flying lesson by our club's treasurer. Obviously your experience there may vary, but simply showing an interest in the hobby as a young person can get you a long way and I'm sure you'll find that members are more than happy to help you get what you need to get started.
Give that a try and I'm sure you will be flying soon enough.