It is often stated that Humphry Repton landscaped Dagnams. It is by no means certain that he did. What is known is that he did designs for the pond near to the house (Lily Pond) There is no evidence that he did much more than that. All of his major works were usually detailed individually in a "Red Book" one for each contract. No Red Book exists for Dagnams.
Below are references and notes from the illustrated work Repton in Essex it is the result of research undertaken by the Essex Gardens Trust with contributions from Georgina Green of the Woodford Historical Society and it is edited by Fiona Cowell.
In 2011 it was out of print. Del Smith
Below figures 237 and 238 from Fragments
Below is the actual text from Repton's Fragments
IT often happens that a piece of water, whether natural or artificial,
forms the boundary of a pleasure-ground near a house, and makes an obvious
line of separation betwixt the dressed or mown lawn and the park, or ground
fed by cattle. But water is not a sufficient fence on all occasions; for,
unless very deep, they will wade through it, and, however deep, deer will
swim across. In some cases, as at "Woburn and Long-leate, a wall
has been built of sufficient depth below the water-surface, to prevent
animals from making good their landing: but in the winter this is no fence;
and, while the ice remains, they must be either kept out by a temporary
line of hurdles, or driven away into a different part of the park; otherwise,
in one fatal night, a herd of deer, or a drove of bullocks, will destroy
the produce of years in a shrubbery, pleasure-ground, or flower-garden.