It's so bloody annoying. They ruin them, then complain that the school doesn't spend enough on updating itself like, new facilities, redecorating, tables & chairs etc.
lol my mate Brin is the owner of the OnePlus One lol, it's a great phone I would definetely recommend. Any im not even kidding he is the creator lol.
Well, have you looked into windows phones? The HTC 8S looks good and is under budget (I think 150 or 160 pounds). It also has a decent screen size and audio. http://www.htc.com/uk/smartphones/htc-wp-8s/
Although the name Brin doesn't show up anywhere. http://en.wiki2.org/wiki/OnePlus http://en.wiki2.org/wiki/CyanogenMod
If you were to get that, I'm fairly sure I've seen it for £150 at ASDA (I work there). I'd stay away from Apple, because you aren't going to find anything decent for £200 from apple, iPhone 4 s is out of date now.
I primarily assumed because the company just launched their product this June, and hasn't been around for more than two years if I read the page correctly.
On the iOS side, a used iPhone 5/5S if you can find one at your range. Shouldn't be too tough. On the Android side, a Moto X or OnePlus One.