Comes in a pack marked "Kosher Salt" from Sainsbury ~ Don't ask me technical stuff ~ I just look at the recipe and bung in whatever approximates to that.
I did run the Kosher Salt question past my lady (she being Jewish but not practicing like).
She gave a very Yiddish shrug and said something about a good way for Rabbis to make money out of fools.
NB A Yiddish Shrug is an exaggerated movement up and then down of the shoulders whilst the hands are extended to the side, palms upward. Unlike the very similar French Shrug the Yiddish version does not involve any puffing out of cheeks but is accompanied by a very heavy and elongated sigh ending in "Oy vey" as the eyebrows vanish into the hairline. Try it in front of the mirror. If you have even the slightest Jewish ancestry you will soon perfect it, if you haven't then you'll never get it quite right.