On Commsec (not sure if ANZ would have something similar) you go...

On Commsec (not sure if ANZ would have something similar) you go to TRADING tab and then Confirmations. You then can enter your dates so you should be able to go back to your first trade date and once the list of trade comes up if you click on Security (ie the header for the stock code) and you can sort by code - ie so all NST codes come up together. You can then download a CSV and sort in Excel. I also keep a spreadsheet which I did from the start to keep track of my actual purchase prices including Brokerage - I use this to check against Commsec and also edit my Commsec purchase price because when you buy in a SPP Commsec doesn't update the new total purchase price for that stock - It is a bit time consuming to start with but I fnd if I update it as soon as I buy or sell a share it is reasonably painless to keep track of and that way I know my position before Tax time ( and I provide my spreadsheet to my accountant which also reduce my accountant fee as they spend less time doing the grunt work).