Hi,
I didn't get the Blessed Herbs kit over the counter, but by mail order from the States. I guess you could do the same if you had to.
I have an idea that the Blessed Herb "digestive capsule" was important, as well as the Bentonite & psyllium, so if you're going to do-it-yourself, it might be worth trying to replicate this in a fairly detailed way, with herbs from your herb-supplier. (Perhaps that's what you meant anyway. Sorry if I'm being a bit obtuse here).
I didn't have the confidence to do-it-myself the first time - I wanted a kit that would give me everything, even down to a dosage calendar. Next time I'll be happier to do it myself.