Free - good choice to go over part of roof (5,4)
I believe the answer is:
ridge tile
'roof' is the definition.
(I know that ridge tile is a type of Roof tiles)
'free good choice to go over' is the wordplay.
'free' becomes 'rid' (to be free of something is to be rid of it).
'good' becomes 'g' (abbreviation).
'choice' becomes 'elite' (I've seen this before).
'to go over' shows that the letters should be reversed in order.
'elite' in reverse letter order is 'etile'.
'rid'+'g'+'etile'='RIDGE-TILE'
'part of' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for ridge tile that I've seen before include "slab" , "item needed on roof" .)