Cross hallmark

by Paul
(Christchurch, New Zealand.)

I purchased a gold ring that the vendor said was 19th Century and 10carat. It has markings of "a very vertical oval 'O' followed by a horizontal small oval 'O' with a bar below and another below, followed by a 'B' and then a German Cross like used in the war". Do you know what date the hallmarks suggest? Thanks :)