A manually operated, electric rocker switch or climate control roof vent can be retrofitted easily to a conservatory roof glazed with polycarbonate, costly if glazed with glass.

The vents are fitted between the glazing bars but it is best to use units that comply with the roof system. If your conservatory is less than 10 years old it will most likely be by one of the following system manufacturers, Ultraframe, K2, Global, Synseal, or Wendland.

All of these manufacturers make their own vent systems, to identify your roof manufacturer look at the end of the glazing bars; the end cap usually has the company logo on it. This situation will only deteriorate if left as it is, suggest to the land lord that the sooner it is resolved the less it will cost in the long run.

One of the companies I own manufactures conservatory roofs of one of those systems listed above.

"he is going to fit two air bricks to the conservatory walls"

That should help considerably. Ask for them to be fitted at opposite ends of the conservatory, but see if you can get one fitted in the middle as well. The more air that moves through the space the better. If there's a door into the house leave it open when you can, and open a rear window. The pressure imbalance between the front and back of the house will ensure that the maximum amount of air is drawn through the airbricks - it's similar to the air-flow that causes doors to slam if you open both back and front doors.