In April 1905, the NSW Cricket Association promoted the club to the first-grade competition. However, in doing so it was decided that Manly Cricket Club, as it was called at the time, would be combined with Mosman and took a new name - the Middle Harbour Cricket Club. The Association decided, however, that the Club's boundaries would remain within the Municipality of Manly, and that the territory within the adjoining Municipality of Mosman would be neutral territory.

The decision was hotly protested for some years by the Club's committee who felt strongly that as the district was part of the Electorate of Middle Harbour, it should have been included in the Club's boundaries, and that players resident in Mosman should be compelled to play with the new Club.

https://www.cricconnect.com/profile/338/manly-warringah-district-cricket-club/blog/2505/name-change-to-middle-harbour-cricket-club