Oh, well then I just don't know.

Perhaps Thomas
was 2nd son, but went and bought land outside the manor after the eldest brother William became tenant there, got married, had kids, etc. and just didn't want to live there? Then after William and then later the mother died,, mummy's boy Robert applied for tenancy (and only got married later).
It'll have to wait until tomorrow now, when fresh eyes may help something else emerge!
Thanks for your help.
