Feeling less clear over site of recent parties (6,3)
I believe the answer is:
number ten
'site of recent parties' is the definition.
(10 Downing Street)
'feeling less clear over' is the wordplay.
'feeling less' becomes 'number' (more numb).
'clear' becomes 'net' (as in net profit).
'over' is a reversal indicator.
'net' written backwards gives 'ten'.
'number'+'ten'='NUMBER TEN'
(Other definitions for number ten that I've seen before include "Maybe X" , "PM's residence" , "centre of government" , "Prime Minister's official residence" , "PM's house" .)