Procession of figures not unknown in part of Ireland (9)
I believe the answer is:
countdown
'procession of figures' is the definition.
(sequence of numbers)
'not unknown in part of ireland' is the wordplay.
'not unknown in' becomes 'count' (I can't explain this - if you can you should give a lot more credence to this answer).
'part of ireland' becomes 'down' (County Down).
'count'+'down'='COUNTDOWN'
Can you help me to learn more?
(Other definitions for countdown that I've seen before include "5-4-3-2-1" , "Numeric process immediately prior to launching spacecraft" , "It ends 2, 1, zero" , "The reckoning" , "prelude to firing" .)