Pretty appealing to a child, it is! (9,3)
I believe the answer is:
chocolate box
'pretty' is the definition.
(I've seen this before)
'appealing to a child it is' is the wordplay.
I cannot really understand how this works, but
'a' is found in the answer.
'child' could be 'ch' and 'ch' is present in the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for chocolate box that I've seen before include "twee" , "sentimentally appealing" , "Ever so pretty externally" , "its contents may be plain" , "sweet carton" .)