Girl turning up with flower is one for meeting? (8)
I believe the answer is:
attendee
'is one for meeting?' is the definition.
(someone attending a meeting)
'girl turning up with flower' is the wordplay.
'girl' becomes 'netta' ().
'turning up' says the letters should be written backwards.
'with' is a charade indicator (letters next to each other).
'flower' becomes 'dee' (River Dee).
'netta' backwards is 'atten'.
'atten'+'dee'='ATTENDEE'
(Other definitions for attendee that I've seen before include "One shows up" , "Person who is present at an event" , "Mixture for soaking meat in" , "One going to, eg, conference" , "One coming" .)