In looking through the book "War Cars" by David Fletcher on British armored cars in WW I Page 73 mentions that the cargo of the SS Shirala sunk on 2 july 1918 by the UB57 included 4 Canadian Russell armored cars based on US Jeffery Quad trucks a Russell-Knight Scout car and most of the units spare parts were part of the cargo and where lost when the ship was sunk. 16 other Russells did manage to make India in other ships. It looks like they had a spare parts problem. I hope this is of interest.