Suspected Baxi 105e diaphram issue

Hi guys absolute novice here. I have an issue with my Baxi 105e combi boiler. When I turn the shower on it doesnt seem to activate the hot water. The bathroom sink does as does the kitchen and there are no problems with the heating. Ive been told there may be a hole in the diaphram. I ordered the part online using the code on the boiler label and when I went to change it I noticed the diaphram seemed a lot bigger than the one in the boiler. Ive looked at loada of videos and mine only has 4 screws not 6. Am I missing something here? Every baxi 105 e Ive seen online seems to have 6 screws and be alot bigger. Any advice would be much appreciated

105e or Instant 105e?

you are changing the wrong diaphragm, the DHW faces you at the front of the diverter valve and has two small pipes going in to it, that is the diaphragm that you have and need to change, just isolate the cold water inlet and open a hot tap till water stops running, be sure to cover the electronics with a towel or similar while doing it, the diaphragm housing with 4 screws is the pump proving diaphragm, if your heating is working leave that alone

View media item 31064There you go.

if its just the shower playing up i would be changing the venturi as well as the diaphragm but yep sounds like an instant with 4 screws