I know, but that page has a serious flaw - it's fixed in chronological order. Without a search/sort function, it's a big job to manually read through over 5000 entries to find one game. And even though I don't have to read all entries because I don't have to read that far back, it still isn't conclusive; I may miss the entry I'm looking for, and even if I find it, it will only tell me when it was redeemed, not where I got the key from - it might have been redeemed from another bundle and so on.
That and I was confused as to why it wasn't showing as redeemed - I seem to remember that only another game was left unredeemed - hence the warning above.
But thanks for the tip anyway.