Your great grandfather Leonard Clark born 1883 in Fordingbridge, Hampshire, mother's maiden name INGS.
William CLARK and Jane INGS married in Fordingbridge in 1881.
Leonard Clark and Bessie Rolls married in Christchurch registration district in 1903, this is the district for Pokesdown.
The family lived in Paisley Road, Pokesdown, with William and his siblings Percy, Nellie, Winnifred and Alfred.
All this indicates the birth BumbleB found in Christchurch is the correct one.