Lumen, the general rule is that capital letters should not be dispensed with in the case of proper nouns, but may be used falsely for common nouns, verbs, etc to deceive or for surface reasons.
This is what Ximenes had to say about it:
"May one use a capital where it isn't needed in order to deceive? May one abolish one where it is, strictly speaking, needed, in order to deceive? My answer to the first is: Yes, at a pinch; but try, if you can, to put the word first in the clue or after a full stop in the course of it. My answer to the second is: No!"
From 'On the Art of the Crossword'
So 29d does not breach Ximenean principles.