Reddit mentions of Liberon Blonde Dewaxed Shellac Flakes, 250g

https://www.amazon.co.uk/Liberon-BDS250G-Blonde-Dewaxed-Shellac/dp/B000TAWD1U here's a link for you.

It should be quite easy to find at any shop that sells supplies for woodworking and laying one's own floors, along with sole wholesale suppliers of materials for manufacturing clothing, because shellac is what they spray on felted hats and things like that to keep them stiff and in shape. To dissolve it you're going to want to use pure ethanol, sometimes you can find it sold to drink as pure grain alcohol, but it's much cheaper to get pure grain or corn ethanol fuel from a shop that sells farming supplies and hardware, as that's what people use to fuel their tractors and such. A lot of synthetic products that are toxic are sold as shellac, which is why I prefer to buy it as flakes than as an already mixed liquid, that way you know that it's the real thing. Japanese lacquer also works but it's ridiculously expensive.

Oh, you do. Shellac comes either pre-mixed or in flakes that you dissolve in alcohol, I prefer the flakes. It is not a brand name, but a description of a substance, made from excretions of a beetle somewhere in India. A very old finish by itself and excellent. Google Wikipedia on shellac. Here's Amazon.uk link where it is sold...........................................................................
https://www.amazon.co.uk/Liberon-BDS250G-Blonde-Dewaxed-Shellac-x/dp/B000TAWD1U..................................................................
The idea is that a light mix, called a "spit coat" seals the grain very lightly, enough so the stain is still absorbed into the wood so you don't have the stain being absorbed more by one type of grain than the other, and evens out the finish. After the spit coat dries, you go over it with fine steel wool, then apply the stain. As I said, if you are going for the blotchy look, you don't need it. But for my taste, an even layer of color is preferable.