Hi, I'm really sorry for the simple question but can anyone tell me how to change a kitchen cabinet downlight? They are not halogen and are the circular kind. i have managed to pop out the light bit from the surround but I cannot manage to open the part that seems to have a bulb in it. I have tried twisting it clockwise / anticlockwise and prising it with a screwdriver but no luck. Do I have to replace the whole part? Any help would be very much appreciated.