Patronising Spanish fizz that is bottled in large runs (8)
I believe the answer is:
cavalier
'patronising' is the definition.
'spanish fizz that is bottled in large runs' is the wordplay.
'spanish fizz' becomes 'cava' (I've seen this before).
'that is' becomes 'ie' ('i.e.' can be a synonym of 'that is').
'bottled in' means one lot of letters goes inside another.
'large' becomes 'l'.
'runs' becomes 'r' (cricket abbreviation).
'l'+'r'='lr'
'ie' going inside 'lr' is 'lier'.
'cava'+'lier'='CAVALIER'
(Other definitions for cavalier that I've seen before include "... King Charles, canine breed" , "Civil War participant" , "'Thoughtless, offhand (8)'" , "one caught laughing by artist" , "Courtly gentleman or being offhand" .)