I don’t know about coffee roasters in Chichester Harbour but premium, speciality coffees, is no problem.
You don’t get cappuccinos, laartes or flat whites at the cafe on Platform 2 in Emsworth. Just a house coffee in a plunger with milk, without milk or if preferred with condensed milk. It is a koffie liosk at a railway station.
But under the counter there is a selection of some of the local artisan roasts for the very curious.