In my seafaring Lpool family "when Dick docks" means "don't hold your breath" or, NEVER! Its origin easily pre-dates that Dick Lewis rubbish.
In the 1890s a new (or fitted out) ship (see Lloyd's Register) by the name 'Richard Donnelly' (a well-known local) put to sea and sank before it got out of the Mersey. Ever since, the phrase has been a derisive dockland slur at a lack of competence
by either shipbuilders or sailors and was still common parlance when I was a lad in WW2 Everton.