1 hour ago, barolo said:Based on what @Kasia, who posted the recipe, said, this looks look like it would do the trick: https://www.amazon.ca/Pearce-Duffs-Assorted-Blancmange-146g/dp/B0051C0Q92
Indeed but at $20 per ($9.99 + $9.99 shipping) that is an expensive proposition!
Edited to add:
In 2008 according to this, a package of powder cost 64P in the UK.