Thanks, Keith. I am, of course, making a rod for my own back. I've got 150+ already uploaded to sort out. But then I have another 3000 in my actual tree which I'd like to add. What I really need is a conversion program, but that wouldn't work because of the varying ways in which I've created my tree. One bonus of all this is that it has shown up faults in that tree, which I can now correct.
But in the end Wikitree will stand or fall by its reliability. I only found it a few months back and I love the idea.