Walker & Hall Demitase/Tea Spoon

I have a Walker & Sons demitassse/tea spoon which my mum had bought back in the early 1960’s from a antique/vintage store.

The spoon I was able to find (by the front hallmark) is from the CCN Portuguese Steamship Line. The hallmarks are as follows:

Front: Ship steering wheel with C.C.N (twice) and Lisboa (Lisboa must mean Lisbon because I could not find a ship of theirs with that name) inside the wheel. A #1 is below the wheel.

Back: Walker and Hall (written out, not abbreviated), an S in a circle, an F in a diamond, a flagpole with flag that has W&H inside. There is also a large S and 17 below that.

I’d like to know what particular ship this was from, the date of this spoon, if it silver or plated and value if possible.

Thank You ! :smiley: