Hi, Krauze catalogues shows “Est. 5 000 000”. See here: https://numismaster.com/MC_17656
This coin is one of the most popular coin from Alderney, definitly with huge mintage, much bigger than 5000 pieces.
On the other hand, it's hard to belive that this can be 5 millions (but definitly more than 5 thousands), so I removed mintage figures and put this info about 5M as a comment.
5000 pieces is the mintage for Silver proof version and additional 500 was for Silver Piedford (which is confirmed by CoA - photos of CoA on ebay auctions).