Thanks for the info Simon and glad to be of help Michael I have some other errata:
From the book "The Russian Military Air Fleet in World war I"
has the British merchant ship King David sunk by the U49 on 10 July 1917 with a cargo of 46 Nieuport and Farman aircraft for Russia.

It also mentions the merchant ships Variol and Stormy Peteral sunk going to North Russia carrying Sopwith 1 1/2 Strutter aircraft. They weren't sunk by enemy action so I guess they were lost either in storms or accident. It looks like sailing to north Russia in WW I was almost as dangerous as it was in WW II.