Fitting C3 headlight bulb, nearside?

I had great difficulty changing this bulb and in the end paid Halfords to do it. It cost £5 and about 20 mins of the guys time! I now find, 2 weeks later that the headlight is steaming up. Can anyone advise how I can resolve this. I am wondering if he hasn't fitted it 100% correctly, though the light works perfectly. Its really agravating me to see a steamed up light. Help!