David, I have friends who have used a Trangia cooking stove on their boat (and in their house truck) with great success. It works on the same principle as the Origo, but if you go into one of the larger camping stores, they usually have a kit for sale. They do teensy weensy ones for backpackers, but my friends have one that has a proper stand and heatshield and came with its own pans. For your cat, I should have thought they'd have been ideal.
BTW, if you buy ethanol (rather than meths) from Wynn Fraser in Whangarei, on the label it tells you to water it down by 20% for cooking. So it's cheaper than you might think to cook on. (Does it take 20% longer to heat the kettle, one wonders.)
And talking of kettles, I have found a Simplex kettle on E-Bay for a tenner!! This should speed up heating my water - they are designed to be used over a medium heat - and it also looks beautiful; apparently it has a whistle built in to the lid. Unfortunately, it isn't chromed and because of my OCD I shall have to polish it!