I need some help with citing a particular document. I downloaded some digitized images from TNA (UK) and now I'm really confused how to cite them. The exact item I downloaded can be found here: http://discovery.nationalarchives.gov.uk/details/r/C1733893
The document itself is a collection of ship registers compiled for 1875 from various Port Registrars in the British Colonies, including Canada, Australia, India, etc. I want to cite only one page of this document, that for Londonderry, Nova Scotia, specifically the registration of the barque Wave Queen, official no. 71342, built 1874 Londonderry, N.S. The page for Londonderry is attached, extracted from the whole and rotated 90 deg. CW for legibility. I plan to add the citation of the page onto it and add a citation for the whole document to the PDF I downloaded in two parts and combined. There is a number  stamped on the page; these numbers are consecutively stamped on each right-hand leaf.
So the first part is "Barque Wave Queen, official no. 71342, registry of Londonderry, N.S. [Nova Scotia]" Do I need to include the (extremely) long title of the form?
The next part is trickier. The document is BT 162/32, but the description given for that reference is simply "BT 162. Plantation." The description uses the singular word "Plantation" [which is referring to Colonies here and later is changed to "British Overseas Dominions and Protectorates"], but the document contains records from all the Plantations. It also doesn't say what BT 162 is. So I was thinking about doing "114, BT 162/32 Registry of Shipping and Seamen: Annual Lists of Ships Registered, Plantation[s] 1875"
Part three: "digital images, The National Archives (TNA), http://discovery.nationalarchives.gov.uk/details/r/C1733893 : 2017." The URL I give is its catalog page; you have to place it in a cart, checkout and then from your order status screen, you can download the document in two parts. [this is what the link looks like for part 1 -- http://discovery.nationalarchives.gov.uk/account/yourorders/downloadpreparedfile?id=BT-162-32_1.pdf&iaid=C1733893&reference=BT%20162/32&ordernumber=I/1607901541...
So putting it all together: Barque Wave Queen, official no. 71342, registry of Londonderry, N.S. [Nova Scotia]; 114, BT 162/32 Registry of Shipping and Seamen: Annual Lists of Ships Registered: Plantation[s] 1875; digital images, The National Archives of the UK (TNA), Discovery http://discovery.nationalarchives.gov.uk/details/r/C1733893 : 2017.
Does this look correct?
In the document, numbers are stamped on each right hand leaf. Should these be called folios or pages?
It's one document but downloaded in two pieces. Do I need to cite it as part 1 and part 2?
Thanks so much for your help.