Sealed side indicators

Hi,
one of the round side indicators stopped working, checked and bulb gone. As I couldn't find replacement in time for MOT I decided to try and split lens from bulb holder.
Method - put 2" - 3" of boiling water in saucepan, suspend unit into water lens first being careful not to let lens touch bottom of saucepan. Do this for 2 to 3 minutes, keeping the water boilng gently during this time. (I suspended unit using pliers around plastic bulb holder). After 2/3 minutes remove from water and using gloves or towel to hold unit, gently prise around the the inner edge of the lens where it meets the bulb holder with a thin screwdriver, the soften glue will now let the two pieces come apart. Replace bulb. I put the two pieces together again and then sealed around back of lens and bulb holder with clear silicone for easier removal in future.