Many thanks, barretter. Your single hint cracked it open for me. Only problems left are to explain the pair of entries including the one I mentioned, and also to parse the second U answer.
Thanks Barretter. If that is correct- and I think it must be - it is a slightly disappointing end to a really good puzzle. Would have been wonderful if the created words had been real.
Dylan, do you mean the two BR clues? In the first one, "tea" is "brew" and it's "nigh" ; in the second "tracks" can be "routes". For the second U clue, look up capital U in Chambers.