The Land Registry FAQ page: How do I find out who owns and/or has the responsibility for the boundary fence/wall/hedge of a property? contains an example image and description which I think could be better (clearer and more helpful). I don't think it has enough 'T's to be able to explain the meaning of them.
Perhaps this one showing a fairly typical row of 4 semi-detached houses (plots 30-33) might be clearer?
If I'm reading the image & description correctly, as there's no explicit mention of the boundary fence ownership & responsibilities in the description, going by the inward-facing 'T's, plot 33 owns & is responsible for the Northern & Eastern fences, but the 'T' on the Western-most boundary fence and no contrary mention in the description, suggests that it is the responsibility of Plot 32.
It also suggests that plot 30 (probably owns &) is responsible for 3 lengths of fence, although that's a little speculative, as I have not seen their deeds with highlighting & description.
I'm sure someone who knows their stuff at the Land Registry could word it better, but I think there's enough ambiguity in the current example, for me to need to ask the FAQ again (which I just did - I'll update this page if they respond in an intelligible way)...
UPDATE: They did not respond directly to me, but I've just re-checked their FAQ and they've re-vamped the site (breaking the previous link) and put in a different example, which mostly agrees with my text above ;)