My new and first baby emp doesn't appear to be eating at the moment, it's been four days since it's eaten, should I be concerned or is the little chap simply full? It's still very active just not interested in it's grub?!

No need to worry dude..thats normal,my baby emp didnt eat for about a month on her premolt stage..

Nothing to worry about, especially if it's approaching a molt. As long as it's otherwise active you should be OK.

You are fine, my emperor went on her first fast two days ago. I figure I'll try again in a couple days, and she is still active like yours but not as young. It's normal for them to do that, I'm sure you won't have any issues. good luck.