GY204 Northern Gem
I'm pretty sure you must be aware of the book Coxswain in the Northern Convoys by Sid Kerslake. For anyone that isn't, it is online at Naval-History.net:
http://www.naval-history.net/WW2Memoir-RussianConvoyCoxswain.htm
There are quite some references to Northern Spray in it, as well.
Here's a little item from the Times on the Gem:
The Times, Wednesday, May 13, 1953; pg. 8
GRIMSBY CATCH LANDED IN HOLLAND
The Grimsby trawler Northern Gem, which landed 33,000 stones of fish at Ijmuiden, Holland, on Monday, was making an experiment, the owners said yesterday. "Rather than let our ships lay up I would prefer that they land their catches on the Continent," said a spokesman of the firm. "It does seem fatuous that German ships should discharge at Grimsby while we send vessels to Holland, but it is preferable to laying up ships."
By the way, someone mentioned in a post about the Grimsby Telegraph having pictures. Their archives are online so it is easy to check whether they hold a picture of a particular trawler or not. I am guessing everyone with an interest in Grimsby trawlers already knows this, but I can post the URL if anyone needs it.
Hilary