My goodness! Typical Ascot gear's time-consuming (5,4)
I believe the answer is:
fancy that
'my goodness' is the definition.
(both are expressions of surprise)
'typical ascot gear's time-consuming' is the wordplay.
'typical ascot gear' becomes 'fancy hat' (fancy hats are worn at Ascot racecourse).
'time' becomes 't' (abbreviation).
'consuming' is an insertion indicator.
'fancyhat' going around 't' is 'FANCY THAT'.
(Other definitions for fancy that that I've seen before include "Imagine!" , "exclamation of surprise" , "Well I'm blowed!" , "goodness" , "Gosh" .)