Constant Drip from Gas Boiler Exhaust pipe when in use

Hi
I recently had my gas provider service my gas boiler and they mentioned that there was a constant drip from the outflow outside the house which is linked to my gas boiler in the kitchen. They didnt do anything to investigate it, but they said it could be a problem and needed to be looked at, although there was no safety risk. Everything (hot water and rads) is still working fine, but I am concerned as I hate the thought of anything gas related not operating as it should, but at the same time don't want to spend money having it looked at if there's no problem. Any advice welcome on what I should do with this.