It's all very well to be nocturnal if you're happy with it but it's clearly bothering you. First of all I would say ditch the lucozade as this will give you false energy patterns. Have you tried all the usual sleep remedies, like listening to some relaxing music, having a bath, drinking some warm milk etc before you get into bed? There are also herbal sleeping remedies which can really help to relax you. Apparently having a messy room can stop people sleeping so make sure your bedroom is tidy. If you think the stresses of sixth form might be affecting you, try writing lists of things you want to accomplish each day and ticking them off so you can review them in the evening and see how much you've achieved. If things are bothering you, write them down so you know they are under control and you can sort them out the next day, rather than worrying about them in bed. If you get into bed an hour before you actually want to go to sleep and lie there with the lights off then you give yourself plenty of time to be asleep by the time you want.
If none of the normal ideas work then you could consider trying to move your sleep pattern forward instead of backward, i.e. instead of going to bed earlier and not sleeping. Try staying up a couple of hours later each night so that you move your natural bedtime through the day to the evening rather than back from the early hours of the morning to the evening, if that makes sense? E.g. if you last went to bed at 12.30am, push yourself to stay up til 2.30 so you're really tired. Set your alarm for 12 midday and make sure you get out of bed, so you're not tempted to sleep til you're not tired at all anymore. The following night stay up til 4.30am, then set your alarm for 2pm. The following night stay up til 6.30am and get up at 4pm. Keep moving the times forward by a couple of hours, always making sure you have little enough sleep that you will be tired by the time you get to bed, until you arrive back at a sensible bedtime of say 10.30pm and a sensible waking time of around 7.30am. You probably will need a week off college to sort it out in this way but I believe half term is coming up? You will also need to explain the situation to your family so that they can assist with leaving you to sleep and getting you out of bed at the right times. It is a fairly drastic idea but I have anecdotal evidence that it does work very effectively and if you can maintain the results afterwards it's well worth the weirdness of staying up all night watching rubbish telly.