Thanks to all for the info. Not sure about the "silver spoon" reference – I guess maybe it's the other leading brand of sugar in UK?
Anyway the article was in a print magazine, not online. The article claims sugar can be used exactly the same way as commercial case hardening powders, ie dip the hot part in it, heat to red heat, quench, repeat, etc. It did not say whether it will work with pack hardening in a closed stainless wrapper in a furnace or forge or not. I would think there would be a lot of flame and (sticky) fume off a large bit of sugar in a pack hardening scenario.
I'll mess around over the next week or so with some sugar re the case hardening (and I won't bore you all with our local brands) and advise how it went vs commercial case hardening powders. I'm sure the sugar will smell a lot better than commercial stuff and it sure is a lot cheaper.
Probably have all the neighborhood kids coming around looking for campfire roasted marshmallows….
Thanks again JD