The British army troops are from 1/Seaforth Highlanders, in Crete from March 1897 to November that year. It’s difficult to make out from the photograph but given the number of Naval officers in the background, it’s more than likely that there are British marines and sailors in the shot.
The postcard is stamped as being posted in 1904 in Canea. The Germans and Austro-Hungarians left Crete in early 1898 and the Ottomans were evicted in late 1898, so there’s a good chance the photographs date from 1897/1898. probably taken in the Canea/Suda Bay area.