Help interpret a W&H mark on a heart shaped salt dip

Hi- My mom collects antique salt dips and has hundreds. She catalogs them all with date, maker, history, etc. She can not find any info on a heartshaped cut glass salt in a silver stand. Can anyone help interpret the mark that is on the bottom of the salt? Time period, maybe? Any info would be helpful. Thank you!
WHSaltMark (2) (375x500).jpg

W&H is the Sheffield (UK) company Walker and Hall and this is a silverplate mark. The “A” indicates the plating quality - not as good as A1 but better than B.

The Greek letter phi is a date code used only by Walker & Hall. One of our contributors has produced a reference for these date codes which is available via eBay under the title “WALKER & HALL, MARKS & DATE LETTER CODES ON SILVER PLATE”.

Thank you Silvermakersmarks for the book reference. The date is 1904.

Hope this helps.

Paul.

Thank you! This was very helpful!