I think canvas holsters came after WWI. I believe the photo immediately below depicts what was issued for "Land Service".
I thought the holsters shown were open at the bottom as well as at the top, so the barrel could protrude slightly from the bottom, if necessary./QUOTE]
Like this?! South African Union Defence Force, mid 1930s. Mk VI .455 Webley in 4" holster. During the 30s the UDF was starved of funds, with very little money for anything new, let alone holsters!
Sorry about the quality, but it is a scan of a photocopy of a print in the archives. I must go back and photograph the print directly.
Peter