What you do is get it wrong, blow the main fuse(plunging everybody into darkness) then wait whilst they start blaming you.
Current regulations make it illegal for you to attempt a repair for the reasons above. Especially since you've just had a leak in the ceiling fixed. Water & electric don't mix very well.
Is it the bathroom or the bedroom?
You say bedroom, they say bathroom.
If it is the bathroom, they've given you some pretty stupid advice about taking a lamp, presumably plugged in, in there.
Have a gander...
https://www.citizensadvice.org.uk/h...irs-what-are-the-landlord-s-responsibilities/
https://www.electricalsafetyfirst.org.uk/guidance/safety-around-the-home/bathroom-safety/