1999 Vauxhall Corsa Timing Chain / Belt

My friend has a roughly 10 year old corsa and recently after a trip from Middlesborough to Manchester the car ran out of oil, presumably due to a leak somewhere, when we turned it back on after the journey home (which was fine all the way) the engine was banging like something was inside it. After a bit of research we came to the conclusion that it's probably the timing belt being worn or corroded but my question is whether it is a chain or belt? I've looked online and can't get a straight answer anywhere, it's the ecotec engine and it's a 1.2. I have also heard that's there's a specific Vauxhall tool for replacing the belt, is it possible to replace it without using this tool? Other than the big-end bearing, is there anything else which could be wrong with it? There was 3 quarters of a full tank of oil before we set off, we didn't check it before the return journey but there were no problems then, only after the car had had 15 minutes or so to settle down. Thanks a lot.