Who do I ring to sort out a suspected raining in chimney?

I have a chimney breast with damp. I have had the damp sorted but it has come back. I’m pretty sure the chimney is leaking because I can hear rain coming in when upstairs at the top of the stack. We have two chimneys and can’t hear anything from the other one. Who would I ring a roofer? a builder? Damp proofing guys?

Garden Hose Guide