2002 Vauxhall Zafira main beam lights staying on when switched or simply flashed.

I have a repetitive problem with my main beam lights. Whenever I flick the beam stalk for either permanent beam or just to quickly flash, the main beam stays on. I have disconnected the battery but when reconnected, the lights come back on. The only way that I have found around this is if the battery is disconnected for a few days but this is neither convenient as I can't use the car in the meantime nor does it always work ! The only sure way I can currently use the car is to remove the main beam fuses but I am not sure whether this is in fact legal practice ?
Has anyone else had this problem & if so what recomendations are there to resolve the issue once & for all. Is there a relay to control the lights & if so where might it be - the car was bought 2nd hand, as seen & I don't currently have an in-depth manual. The only manual I can find online is Vauxhall's owner's manual which is as much use as a flat battery !!!