Hi Barnaby,
Thanks ever so much for doing further research for me.
My 2x great grandfather was Claud Behenna. He was born in 1849 in Kennington Oval, London. He joined the 2nd Dragoons, the "Royal Scots Grays" (RSG) a cavalry Regiment. In 1872, he was stationed in Perth Barracks. By 1872/73, Claud (25) is a Police Constable, "50V" recorded on the birth certificate of my great grandmother in Nunhead, London. By the time of the 1881 census, he was aged 33 and a "Traveller (Mineral Waters)" in Camberwell, Surrey.
I assume that he had left the RSG c1872 and joined the Police and served for there for a period of time. According to other notes, he was a mounted Police Officer, "No. 500". I don't have any original documents for this information, but perhaps he joined this branch due to his army background. If you can find anything further, we'd be delighted to hear about it. Thank you so much for your amazing hard work.
Best wishes, Jimmijam