William Luke Broun, Capt. - Captain Broun

I have found a photo on the London derelict grave yard site, of a Captain William Luke Broun. The graveyard is at Barnes common in London. It is overgrown and has a memorial stone, and I can just make out Commander R.N. lost at sea. I have not been able to find his name on the naval lists,and I cannot get to the archives. I am guessing it is first World war. I would like to find out more about his life. These brave chaps deserve to have their story told. They should not be forgotten.