Problem with that chap twice holding a scoundrel back (8)
I believe the answer is:
headache
'problem' is the definition.
(I've seen this before)
'that chap twice holding a scoundrel back' is the wordplay.
'that chap' becomes 'he'.
'twice' indicates the doubling of some letters.
'holding' is an insertion indicator.
'scoundrel' becomes 'cad' (cad is a kind of scoundrel**).
'back' shows that the letters should be reversed in order.
'cad' back-to-front is 'dac'.
'he' duplicated is 'hehe'.
'a'+'dac'='adac'
'hehe' enclosing 'adac' is 'HEADACHE'.
'with' is the link.
(Other definitions for headache that I've seen before include "Pain in the cranium" , "Major problem" , "Cause of worry/trouble" , "Source of worry (and pain!)" , "Severe problem" .)