You are correct in identifying the hallmark date as 1893 (or more correctly 1893/94 as the hallmark year began during the calendar year) and, in addition the design registration date is 1894. I suspect that you may have found the 1897 date at http://www.silvermakersmarks.co.uk/Make ... WK.html#WJ
. The dates quoted there for this Holmes mark (1897 to 1935) are dates for which the mark has been seen and are neither absolute working dates nor registration dates. Registration dates for marks on that site are specifically quoted as, for example, "(registered Jan 1900)". Next time you check the site you may see that the earliest date will have been altered to 1893, depending on when I get round to uploading the amendment.