Thanks Jill. Mike's page was great reading. My two cats Mollie, exotic Blue & Milner, long-haired tortoiseshell are both rescue cats and have moved house with me more times than I can remember. They seem to cope just fine. After initially searching every inch of their new surroundings they are desperate to be outside so it would only be the water they'd have to get used to really.
Now, apart from saving up some more money, I could do with convincing my other half who is probably busy making some cat size life jackets just in case.