He attracts bats with some difficulty (2,1,7)
I believe the answer is:
at a stretch
'with some difficulty' is the definition.
(at a stretch means in difficult circumstances)
'he attracts bats' is the wordplay.
'bats' is an anagram indicator (slang for mad).
'he'+'attracts'='heattracts'
'heattracts' anagrammed gives 'AT A STRETCH'.
(Other definitions for at a stretch that I've seen before include "With difficulty; without interruption" , "With much effort" , "in one continuous period" , "Running, possibly" .)