Hi Ginstigol,
Those packets are definitely rare, but be patient: I was looking for one of these for about a year, and then one came up for sale on eBay, and around the same time I found the other one on a website, so I bought both of them at the same time.
So they do come up for sale sometimes - I know how it feels to be searching for a rare packet though - it’s a permanent feature of my life!