I too have seen an old family tree that my father acquired in the 50's. I have remained in contact with a Slyfield offshoot family in the states who also possess the same copy. Perhaps when I get time I will endeavour to to a comprehensive upgrade of my immediate branch.
As outlined in a message to someone else here, my immediate line left the Surrey/Middlesex area around a century ago but we soon drifted back to Oxfordshire, Berkshire and Buckinghamshire where most of us now reside.
I have only been to Slyfield Manor a couple of times, and not recently, but I have found a number of curious parallels with the activities of our more distant ancestors and some of us still alive today.