The message
from Guy King contains these words:

The detail on the Land Registry plans of my abode are vague,
disappointingly vague...

"The freehold land edged with red on the plan ..."?

Yeah, but the thickness of the line on the plan is often about a foot
wide on the ground.

In my case the line is the best part of a mm thick and at 1:1250 scale
that is more than 3 feet on the ground. The red ink complete obscures
the real boundary lines on the plan which are probably no more than
0.1mm thick and thus actually thinner than the walls they represent.

--
Roger Chapman