Hi It's quite easy really. Unplug microwave. Unscrew the screw at the side of the microwave and the outside screws around the back of the casing. lift off the casing ( you may have to wiggle it a bit but it will come off. You will see the bulb immediately. Unscrew the bulb. You will need 25w Xbm 240-250v Heavy duty bulb. Reverse the above and put Microwave cover back. Finished.
Shirley
May 2020
Automatic Answer
While you wait for answers, we may have found some information which could help you.