Thank you for your reply, it sounds like I was on the right track.
So, bearing in mind the specs of my mini bulbs [ Wattage = 0.25W , Voltage = 4.5V , hence I = 0.25W / 4.5V = 0.056A ], it sounds like I'll need a Resistor = (220V - 4.5V) / 0.056A = 3848 O. Do you approximate up or down?
And...