Where can I find plans of MDHB engine sheds, Liverpool?

[Stephenwolsten]

I am planning a 7mm scale diorama of the MDHB, LOR and Riverside branch lines in the vicinity of Princes Half Tide Dock, Liverpool.   Does anyone please know if there are any drawings available of the MDHB engine shed/works at Princes Dock (or other sheds)?   Otherwise, I will have to count the bricks on photographs and make some guesses!   More generally, does anyone have any experience of accessing the MDHB archives at the Maritime Museum?  I am wondering whether some of the papers on the MDHB railway might help me.   I have relevant photos by people like Jim Peden and Keith Rose, plus a wide range of Liverpool books, but am always interested in more obscure photos, plans and maps of the dock railways.   Thanks.  Stephen Wolstenholme.