First-rate access to attic? (3-6)
I believe the answer is:
top-flight
'access to attic?' is the definition.
(I've seen this before)
'first-rate' is the wordplay.
'first' becomes 'top' (synonyms).
'rate' becomes 'flight' (I can't explain this - if you can you should give a lot more credence to this answer).
'top'+'flight'='TOP-FLIGHT'
Can you help me to learn more?
(Other definitions for top-flight that I've seen before include "Highest level" , "Excellent -- best possible" , "Superior" , "Of the highest class" .)