Left a German claiming one reward for late night? (3-2)
I believe the answer is:
lie-in
'reward for late night?' is the definition.
(someone might have a lie-in after a late night)
'left a german claiming one' is the wordplay.
'left' becomes 'l' (common abbreviation).
'a german' becomes 'ein' ('a' in German).
'claiming' is an insertion indicator.
'one' becomes 'i' (roman numeral).
'l'+'ein'='lein'
'lein' enclosing 'i' is 'LIE-IN'.
(Other definitions for lie-in that I've seen before include "Period in bed longer than usual" , "time spent with crossword, perhaps" , "Extended bedtime!" , "Extended time in bed in the morning" , "Extended sleep" .)