I've been looking for this as well, I don't have the script, but loved the advert. I can remember it goes something like this (not 100% accurate):
TV: so buy KP skips, the crisps that melt.
Guy: Hey Honey do you hear that, crisps that melt - that aint natural.
Girl: wierd City!
Guy: (Breaking down house) Crispy things don't melt they crunch. It's a fact of life, wadda'ya say crisbo..?
Cat: CRUNCH
Girl: Ooooh, my beautiful hoooome
Guy: Weeeell just maybe....(grabs crisp packet from screen)
GIrl: (eating skips) Frizzly on my tounge...
Guy...WOW WEEE, MEEEELT CITY
Guy: Hey soften up, soften up
Girl: yeah, liquidise, liquidise......
(.^_^.)