I remember them - the Hinders ones, I bought some at least 10 years ago
I think they just fell victim to boilie fashion and didn't sell-
oily pellets changed a bit (most of them) and got dryer
also betaine will be in the ingredients of a lot of them anyway, just not named as such on front cover
Just get some plain Dynamite (black, in the blue bag) halibut pellets mate (one of the only ones left on the market that haven't changed, good old Dynamite are class), and soak them in betaine/good quality VG combo - go light or the pellets will turn to mush - a careful 5-6% glug by final mix weight is the one
don't shake glug in too hard, leave them steeping for minimum a week or preferably several