"Bert and Winnie" or so they are identified on the reverse of the photograph.
Bert may have been  a member of the Hertfordshire  Yeomanry with this being based solely on the local where the
photograph was taken. At the time of this photograph he appears to have been a member of the Imperial Yeomanry
and was preparing to embark for service in South Africa during the Anglo-Boer War.

Cabinet Photograph
J. Dunn - Photographer
Hemel Hempstead, Hertfordshire, England
c. 1900