Because you're a little on the heavy side, I guarantee you can lose the weight pretty quickly. To lose weight, you've pretty much got to consider three aspects: resistance training, cardio, diet and sleep. And you can do all of these for FREE.
Resistance Training:
Calisthenics are your friend here. Every morning give yourself 20 minutes to do the following: three sets of as many push-ups as you can manage. Get a chair and do three sets of tricep push-ups. Do three sets of crunches. Do three sets of twist sit-ups (equal number each way). Lay up on a bench or a firm mattress and do 3 sets of leg raises. I won't go into detail about form, but that stuff is easily found on the web. You'll also eventually want to incorporate weights, but assuming you've never done exercise, this will have a good effect and will get you motivated. As I said, start with however many you can do - just focus on good form (don`t cheat) and build up over time. When I started doing this at 17, I could barely do 3x 15 push-ups. 3 years later when I joined the army, I could bust 100 on a dime. And I've kept up (and enhanced) this routine every day ever since.
COST: $0.
Cardio:
Wherever you can, walk instead of taking a vehicle. If you don't have a chance, make a point of going for a walk every night for 30 minutes. When you've built up a little stamina, turn that walk into a slow jog. Just go as far as you can to get some heavy breathing going. The key to cardio is regularity, so make sure you do something EVERY day that gets your heart going. As your endurance improves, you want to keep ramping up the distance and/or pace so that you keep getting your heart going and eventually get a good sweat going.
COST: $0.
Diet:
For your body type, this is probably the biggest problem and where you can acheive the most results. You're English, so I assume you eat a lot of tasty but disgustingly unhealthy food

So if you have a burger, hold the cheese. Don't have fries with that burger. Eat fruit. Drink water instead of Coke. Drink Guiness instead of ale/lager. Don't snack between meals. Eat as many un-fried vegetables as you can stomach (I hate them too). DON'T HAVE SECONDS! The point is, you're faced with a number of choices every day between eating something healthy or unhealthy. If you make the healthy choice most of the time, you will notice it.
COST: $0 (and maybe even negative!).
Sleep:
After doing all this stuff to yourself, you'll find yourself getting more tired than usual. Give your body a chance to recover by sleeping 8 hours a night. I'm guilty of breaking this rule myself, but it makes a difference.
COST: $0.
Anyhow, there you go. I'm sure there are other guys on the site that can offer even more expert advice, but this will definitely work, and it won't be that hard. From what you said, you're about 30-35 pounds overweight, but the good thing about that is that those pounds are the easiest to shed. I guarantee that if you follow this stuff religiously, you can expect to lose 10 pounds in a month, and it will show. The visible results, the endorphins, and the compliments you can expect as people start to notice you losing weight will all help your confidence and encourage you to get more aggressive and keep trimming down.
Good luck!