There can also be confusion between ... Gillingham in Dorset and Gillingham (Jillingham) in Kent.

I have always had a stammer and went along to a speech therapy course with some half a dozen others when I lived in Gillingham, Kent. In the introduction the therapist got everyone to say who they were and what they hoped to gain from the course. It was, as you might imagine, a somewhat painful exercise. Just about the last person didn't have a stammer at all, but had been sent by his wife because he sometimes mixed up the two Gillingham pronunciations.

For some reason, he never came back after the first session.