Sydney Charles (bc.1881 Sevonoaks) seems to have taken part in the Boer War 1901-1902 in Queens Own Royal West Kent Regiment - reg.no.6983. Plus a Thomas (bc.1878 Seal, Sevenoaks) in the same regiment - no.6835.
So, would seem the photo would have been taken after return from Boer War ca.1902-3.
Annette