Average, as this solution is? (4,3,6)

'this solution is?' is the definition.
I know nothing about this answer so I can't judge whether this works.

'average' is the wordplay.
I cannot really see how this works, but
'average' could be 'middle' (synonyms) and 'middle' is located in the answer.
The remaining letters 'downthe' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).

'as' acts as a link.

Can you help me to learn more?