I just found this thread. Wish I found it about a month ago, which was when I went back to my collection that has been dormant since the '70s to catalog it properly.
Anyway, I have been bag-and-boarding all those old comics when I found a few that had Australian prices printed on them. So these would definitely have been from the '70s, not the '90s as stated in this thread. But now I don't even remember which ones they were so would have to go back through about 20 boxes to find them.
Also I found a couple from pre-1966 that had pence prices. Most of the comics sold in Australia then had US prices and local newsagents put a 10c sticker over the price. So not sure if these were some UK books that were shipped here so they could be sold with pre-decimal currency pricing or found their way here by some other means.