Review

Investigating minor leak in ceiling (probably) due to hot water cylinder above

I would like someone to investigate a minor leak I have got in my ceiling (between ground floor and 1st floor). My guess is that it's due to the water cylinder installed in a pantry just above (1st floor). There is a probably due to a pipe running down the wall and along in the floor to the bathromm next to it (also 1st floor) ... so difficult to see what's going on as pipes are not visible. See photos of small cracks and stain on the ceiling (due to water dripping a bit from time to time) and hot water cylinder in pantry. This is not an emergency situation so no emergency "billing" accepted ;-) I basically need to know where is the leak coming from and the cost to fix it ? Thank you for your help.