Changing a lightbulb don't laugh

[lisalisa]

Pls don't laugh ! I need to change a lightbulb in the ds bedroom . The last time I did this I'm
Sure there was guidance issued not to change it when the switch is on otherwise you'd electrocute yourself ! But how do I know if the light switch is on ? It's a button to press rather than one which flicks obviously to an on position where you can see if it's on ? Also without removing the light fitting how do I know which size bulb to buy ?

I'm not laughing.
Can you post a picture of the fitting (and the bulb in situ?) it would help.

Wait until it's daylight and turn the supply off at the consumer unit. Take the bulb out. Do you have a lamp you can plug in instead until you have changed the bulb?