Old Nick wrote:

I do have to ask, having been frightened by a really tippy boat, how
many people simply never took up kayaking beyond that first try,
having been put off by Mr Zippy's super dooper?

I suspect that it's far fewer than you might think. It seems that most
people get their first taste of paddling by renting boats, which are
invariably wide, stable craft. Personally, I paddled boats that scared
me and not only did I continue paddling, I bought one of those boats (a
Nordkapp)! After paddling it for a while, it felt as stable as a couch
and I now paddle boats that are considerable less stable quite
comfortably. I now know what my limits are and there are a few boats out
there that I won't go near. My girlfriend owns - and loves - one such boat.