Nice thing about the gmail approach is its completely seperate. At any stage just stop using gmail and start using Optus Webmail again.
NB don't forget to update you recovery/authentication email options (bank, etc.)
I migrated it all across from Optus to a gmail address, though I thoughtlessly deleted all the spam from my Optus inbox before I did it so I don't know if the Google filtering would've stopped them. I haven't received any spam since the migration though which is good. It's only been about 7 hours since I did it but I would easily get 1 or 2 spams into the Optus webmail in that time.
One thing I haven't worked out though is how to transfer emails in folders in my Optus webmail so if anyone has any bright ideas there that'd be great.
Looks like you are getting there @MattWood
Have a look at this link for moving your emails from the Optus folders:
I haven't tried it but looks like it should work.
I've put my thinking cap on now I am having a glass of wine.
Before you transfer the emails from your folders, if you are anything like me, it may well be worth cleaning out those that are no longer required.
In Gmail there aren't folders but labels. Act the same.
Are you auto forwarding all emails from Optus?
Have you looked in the Gmail spam folder to see what's arriving?
I actually did have a little clear out and yes there was some outdated junk in there. I've read the article but I can't seem to find anything about emails that are in folders, it seems to be about setting up mail forwarding which I've already done. I don't really want to send all the folder emails separately, there are a couple of hundred of them. I might try moving one or two into my webmail inbox and see if they transfer across to gmail. And yes I have checked the junk folder in gmail and there are indeed a handful of the same spam emails I was getting in webmail. My main problem at least is solved, thanks to you and Peter.
Not sure if Dave's options are working but my thought was to just move the files back to the main folder. If you wanted you could set Gmail to Auto tag the files just before you did it so they get the label you want?
Not sure but just a thought. Otherwise file Dave's example and grab a good drop and just power through the 300 out so one ata time.