The current work in progress is all in pieces on my living room floor whilst I search for the proper way to fit the plot together. It is like doing a jigsaw where you are missing some pieces (probably the edge pieces that hold the thing together) and have been given other pieces from a different puzzle that don't fit.
The book is complete in that it has a beginning, middle and end, but I am juggling the scenes to get a smoother read. Part of this has been to combine characters that have the same function - I seem to write far too many antagonists, and this made the plot feel bitty. But in losing one of the characters I am finding I have gaps - hence looking for the missing pieces.
What has saved me though has been more research. By delving again into the period and real events I have found that I can fill the gaps not with characters but with the character of the landcape of Restoration London which is always fascinatingly strange.
In my investigations into Frost Fairs I discovered this bizarre picture of the frozen Thames with icebergs at least six feet thick, formed when the tide rose and froze. When the tide fell away the icebergs were left above the re-frozen surface making a jagged lunar landscape. London bridge is shown just behind with its houses perched on top. This strange arctic terrain in the middle of London has inspired me to explore the character of the Thames a lot more which enables me to have another antagonist (the Thames) without cluttering the plot with too many characters.