Dianavan,
"Has anybody ever delved into what the other merchant vessels in the vicinity may have witnessed? Haven't heard much about that have we? Why do you suppose that might be?"

Neither side has mentioned other ships.
Are they both trying to hide something?
Perhaps there were no other ships. None appears on any of the images.
One ship supporting Britain is obviously not enough to convince you.
How many would it take?
Are there enough ships in the world?