I was shown a photo of an Ariel 500 single reg. BJD 892 by a friend of a neighbour recently.
The bikes age is estimated at 1948 - 1953. The photo shows the owner Sam Smith on National Service in khaki army uniform late 50's - 60's
A bit of long shot but if the bike still exists I will forward a copy to the current owner.
54 Square Four, 1934 RH500 twin port, 1936 RH500 single port, 1945 RH500 (1936 ) twin port, 1947 VB Buttermilk.