Hi Vic (call me Ed). There are masses of films of Dover on the British Pathé website above.
Can you resolve the question which Howard asks in #3 as it is puzzling me also. Would I be right in saying that the Packet Yard was the series of workshops which now comprise the central section of the De Bradelei Wharf shopping complex?
The document below refers to this complex in Section F "Wellington Dock warehouses and slipway, Dover" and states "Buildings 11 to 14 all belonged to the South Eastern and Chatham Railway and constituted the maintenance yard for the company's cross-Channel steam packets."
http://www.canterburytrust.co.uk/annreps/pdfs/1998/004.pdf