are you sure the glass was glued in as they are nearly always fixed in place with brackets or by a door surround.
if it was held in by brackets and they are broken then the best place to buy cooker spares is from gas-on-spare in halesowen, birmingham. they have a website and do mail order.
before you ring them you would need the model number, serial number, model and manufacturers name, this can normally be found on a small data badge just inside the oven door or on the back of the cooker