VW Golf Plus (2006) - Headlamp bulb constantly indicating as blown - Justine

One of the headlamp bulbs on my Golf Plus keeps constantly indicating as blow. It's always the same side and the warning light comes on usually during the day when the lights aren't even on. Occasionally, it can be reset by unplugging and plugging the bulb back in but on other occasions, it needs a new bulb. It keeps blowing even though I never switch the lights on between failures!