Vauxhall Astra Alternator belt?

On my way to work this morning, my battery light flicked on. After lifting up the bonnet i noticed the alternator belt had dissappeared. Now, what are the risks of driving an hour home as I do not have any tools in my car? The battery is fairly new, and I asked a local garage and they want to charge me 30 quid labour to put a new belt on - thats why i want to drive home.

Thanks for any tips/help.