Extracting postcode from a cell which contains address

Im trying to come up with a formula that extracts the 4 digit postcode from a cell containing an address. The postcode is not always in the same position in the cell, and it wont always be the only 4 digit number as there may be addresses such as 1419 Smith St etc.

Can anyone assist?

Below is a sample from the column (btw, i couldn't attach the excel file for some reason)

915 Nudgee Rd Banyo, Qld 4014 Australia
18/2 armadale street Armadale, VIC 3143 Australia
1 Kohl Street Upper Coomera, QLD 4209 Australia
Level 6, 60 York Street Sydney CBD, New South Wales 2000 Australia
41 Bridge Rd Glebe, NSW 2043 Australia
80 Box Road Taren Point, NSW 2229 Australia
Unit 5 16 Theodore St Eagle Farm, QLD 4009 Australia
1 Wella Way Somersby, NSW 2250 Australia
Level 1, 9 Plaza Pde MAROOCHYDORE, QLD 4558 Australia
The Unicorn Club- MHSOBA, Forrest Hill South Yarra, Victoria 3141 Australia
Suite 32, 21 Aristoc Road Glen Waverley, Victoria 3149 Australia
Cairns Professional Centre 92 - 96 Pease Street Manunda, QLD 4870 Australia
Level 31 King Street Melbourne, VIC 3000 Australia
6 Station Street Moorabbin Melbourne, Victoria 3189 Australia
Richmond Melbourne, 3121 Australia
91 Moreland Street Footscray, VIC 3011 Australia
PO Box 274 Melbourne, Victoria 3205 Australia

ive now managed to attach a table containing the desired result in column B

thank you guys, very helpful!