I recently ordered a quart of Proseal ex Van's during the level 4 lockdown, and it only took a week to get here.
Resene Durepox is a good epoxy primer, and is available from Resene's automotive division. They also sell a product called Hydrafos which is apparently a good acid etch prep (I haven't used it personally though).
Alodine I got out of Henkel in Auckland, I think they sell it in 500ml containers, but it is much cheaper to buy it in bigger quantities..
How much Proseal are you after? I could send you a partial tin that I have here (expired a few months ago, still cures perfectly) to get you out of a bind if you need it? and I'll have another partial tin (non expired) in a few weeks once I finish a tank I'm working on.
Let me know, Hugh 021 901 099