OK, I probably should have gone with something a bit less obscure...
HMS Hartland Point
Indeed a service ship, Wolster. And yes, LT, two different flags.
As Wolster pointed out: "Looks like the Union Jack on the front and the White Ensign on the rear, UJ can only be flown at anchor from the jack mast."
The HMS Hartland Point although commissioned and built by the English in 1944, was transfered to service with the Canadian Navy in 1945. The point of exchange when this particular photo was taken.
Next up: