Who owned this 17th century notebook?

I spotted this item for sale at an auction house which is just around the corner from my favourite eye hospital:



According to the auction particulars there is a family story about the ownership of the book which is now in doubt. We can't see all the pages but I noticed some entries regarding money loaned to a Mary Escott, described as a cousin, and this seems a useful clue.

It would be an interesting challenge to identify the owner before it goes up for sale on 1st May.

London is the obvious place to begin the search, but searching the parish registers at Ancestry there are very few entries for Mary Escott. However this 25th May 1660 baptism at St Andrew, Holborn offers one possibility:



However I can't find a marriage in London and the family don't seem to appear in any Ancestry trees. Any other clues? It doesn't help that events during the interregnum were not necessarily recorded in parish registers.