You know the really old rolled brass case ones? A mate of mine has a rifle but I'm definately not giving him all my ammo for it. Where can he get brass (mail order, he is an Aussie)? He's not after rolled brass. Or can it be formed? Loads anyone?

I know this is a long shot but all help appreciated

Gerard of GS Custom has some Martini Henry cases on his web-site http://gscustom.co.za/ .

Hunter: Bertram Brass will supply wonderful if expensive drawn brass cases for the .577-450, and Bertram is an Aussie firm, located in Seymour, Victoria.
Loading for the "Fat Boy" is rather complicated, as early Marks of the Martini had something like .459 bores, and later marks had .468 bores, and all the Marks were chambered with large necks. As a result, if you are loading for an earlier Mark, you may have to resize the neck so much to grip the bullet that you'll split it through overworking it in just a very few loads.
Suggest you check a couple of sites:

http://www.martinihenry.com/

and http://www.gunandknife.com/cgi-bin/forums/martiniconfig.pl

Keep in mind, this was a black powder round, and the rule of thumb with all BP rounds is that the only safe reload is one in which there is NO AIR SPACE left inside the case. You achieve this by putting in enough black powder to slightly compress it when the bullet is seated.
Best of luck to your friend. There are a lot of chaps in Oz and New Zealand shooting .577-450s.