My tenants are indeed first time renters. There seems to be lack of awareness of dealing with condensation, they even reported the problem as "roof leaks". And my impression is that they expect the conservatory to be a "normal" room, actually they use it as dining room from what I see.
I would prefer not having this conservatory but we bought the house with it and it is unlikely we can get rid of it at the moment. So I will make it clear they need to adjust their way of using the conservatory to mitigate the issue but again from my side I do want to do something to improve the situation, hence the question about adding vents. But so far seems no one has suggested if that could be an option...