What is the Value of antique 18k gold pocket watch signed rigal and strawbaum kimberley made in England?

Does it have a hallmark? Strawbaum is a very rare surname. My grandfather was an antique dealer and his surname was Strawbaum. He was originally trading in Yorkshire but moved to Brighton. I will have to ask my mother for the dates. His father - my great grandfather - apparently left his family with his eldest son and moved to Kimberley to join the search for diamonds. I would be interested to buy this watch if you still have it. I don't know the value but it should be possible to find out from the condition and the date. I expect that someone who deals in antique watches would know the value. My email address is John22L@aol.com. I would be interested to see photos of the watch and the engraving. I'm just guessing but maybe my great grandfather went into business with someone called Rigal in Kimberley.