Yep.
7 - Consumes plat*e of food [5]
*!
I got hung up on it being Linford or the Auction house and couldn't think of any other Christie that it might be!
That's a compound clue, a number of straight clues together.
I heard a root vegetable was owned by this crime writer. [6,9,6]
Ah yes, Carrot Beetroot, the famous flame haired, rubicund flatfoot. When she's not battling with a drink problem she solves crimes by consulting a magical Potato that inadvertently always leads to the vital clue.