Hmm. I'm not sure that you've quite grasped the concept of crossword compiling. The clue should lead you to the exact words of the answer, not just words that sound the same. If you're going to use "ate" for "eight", you have to let the solver know it's an aural synonym. A common (and clichéd) way compilers do this is by adding "on the radio". Your clue would then become the extremely clumsy "nibbled on the radio"---in other words, "ate" sounds like "eight" when you're listening to the radio. Synonyms also have to be precise. Even cryptically, "a corny" is a bit of a stretch to "oak" and I've never heard anyone say "Look at that beautiful a corny tree". Of course, I see the acorn connection but it simply doesn't work as the synonym you intended. I'll let you off with "latch" for "lock" although, technically, they are not the same. A latched door is not a locked door. It can be opened from the outside by simply pressing down on a small lever.
Finally, you indicated that the answer to your clue had two words (5,6). "Eight O' Clock" should have been represented by (5,1,5).
Apart from that, it was brilliant!
Seriously, your clue was very clever but it was WAY outside the bounds of crossword compiling.