1996 Peugeot 106 Battery drain

Electrical problem
1996 Peugeot 106 4 cyl Two Wheel Drive Manual

My car had been running fine with no problems other than I once noticed the speedometer drop down to zero and back up again whilst driving. I have a new battery which I purchased in November and drive my car on average 5/10 miles a day.
Last week when I tried to start the car I realised that the battery was almost drained. I took the battery to the gargage that I got it from and they re-charged it for me. When re-fitting the battery we noticed that there is a faulty connection from the positive to a fuse box that affected the flow of power. We positioned the wires so that the power was good and were able to get one more weeks worth of driving out of the battery. This morning we are back to square one and the battery is almost dead. Any ideas on what is draining the battery or why it seems to happen all of a sudden (i.E. On Friday I drove and the power was all good, no probs at all and by Sunday the battery is so low it won't even operate the keypad immobiliser or turn the engine). We've tried fiddling with the wires again but the power just goes from bad to off - the battery is def low.
Any ideas would be much appreciated! Thank you.