How many Dave’s does it take to change a light bulb? It depends where. We have some down lighters in one of the bathrooms, and they have damp proof enclosures.
Here you can see the internal and external enclosures.
And here you can see the lamp’s attatchment to the lower collar. The spring is quite stiff so the lower plate needs to be pulled and the upper collar needs to be held so that the spring releases the lower collar.