craftgrrl | Gah! Urgent soap help!

Hi girls (and boys...mebbe)!

I want to make some pretty purple ice cube soaps for my sister and brother in law for chrimble, but I'm having a bit of problem locating supplies. I have checked all the local craft shops for glycerin but to no avail (they have soap kits but these are so bad value for money), soapcrafting just isn't very popular around here, I've found mail order supplies at http://www.thesoapkitchen.co.uk but since I'm time constrained this isn't much help.

Anyone got any ideas of other places to try? Or is there some kind of commercial soap that can be melted and poured from a pharmacy? I suppose I could try and find some cheap purple soap and use cookie cutters or something.

p.s. I'm located in the UK