Hi all,
According to Norske Veritas register of 1940 the Gun (LEUJ) was "owned" / managed by Holter-Sørensen, Oslo as Øistein wrote.
She is listed as Holter-Sørensen owned in the Nortraship lists too. A lot of the Nortraship vessels were chartered to MOWT, but they were still managed by the Nortraship (MOWT chartered, mainly from the London office).
As all Norwegian ship in Allied service were managed by the Norwegian Governmental shipping Co "Nortraship", it would be very, very strange indeed, and uncommon, to the Nortraship to let a British company manage such a vessel, as there was no use or need to do so, except to reduce the income from her. It just make no sense, and as this is not covered in the files of the Nortraship, I consider the Wilson management, and LR information as incorrect.

With best regards, and hopefully understandable English :-)
Erling