[Caz]

My boiler is in the bathroom, no condensation problem there, just a slight drip underneath the boiler. it's the kitchen that's the problem.

Yes, you would think the landlord would do something about it. The agents do the urgent repairs that they know about. But possibly didn't know about the heating problem. Just like they didn't know about the drains being blocked, had to get drain doctor out to clear em.
Taking proactive action anyway, and giving the agent evidence of the problem, and will take it from there. If agent can't convince the landlord to do something, will be moving out after six months is up.