I am indebted to the daughter of John Alderson for giving me a copy of part of her father's diary (see here for a peek at that) covering his training in this area during WW2.  

In it he mentions two more ships, which must have been seen regularly in this area at that time, and I have looked up some details:

The Flamant (Flamingo, although she looked like an ugly duckling to me) was a French fishery protection vessel built in 1918. She was 600 tons, steam driven and carried a crew of 53. She was noted as visiting Fleetwood in July 1939. In 1940 she was taken over by the British and renamed HMS Quentin Roosevelt (named after the youngest son of President Theodore Roosevelt, a pilot who was shot down over France in July 1918). She moved to the northwest coast and was engaged in moving men and supplies between Oban and Lochailort. She survived the war and returned to fishery protection duties under her old name afterwards.

The Prince Leopold was a Belgian channel ferry built in 1930 and working between Dover and Ostende as one of four identical ships. In 1940 they were all taken over by the Royal Navy and had the prefix HMS added to their original names. They were all converted for the task of landing infantry, transferring the troops to landing craft alongside. In 1944 HMS Prince Leopold was engaged in training troops to disembark at several local sites, Laga Bay and Kentra were mentioned in the diary. The ship later took part in the D-Day landings, taking US Rangers to the infamous Omaha Beach. After D-Day she continued to cross the Channel with more troops until 29th July when she was disabled by an acoustic homing torpedo fired from the German submarine U621. The submarine was sunk in the Bay of Biscay on 18th August 1944. HMS Prince Leopold was taken under tow but sank before reaching safety. She is still in the news since she is popular with divers and there is a controversy concerning the possible presence of a rack of live depth charges on the wreck.

John Dye 20/3/13