Kiera,despite all the hillarity you still have a leak.A leak at the rear or centre of the car can be touched off by exhaust heat.If it's under the bonnet,the same applies plus electrics involved.If you can't expand your description at all,please ask a friend or neighbour to look.Modern fuel injection systems operate at high pressure and what looks a small leak could become worse when driving.You really don't want to risk leaving it.Go for an early mot and get advice.Geoff.
If it is a rust-hole in the tank, get a new tank. I've tried repairs but they only go again. Once they are rusty one hole will be followed by another.
If it is a bit of pipe fit new pipe.
If it is at the carb you will probably see a brownish stain on bits of engine that are much cleaner than the rest where the petrol has washed all the oily dirt away.
Crawl about underneath it and find out where it is leaking from.