Curved fingerboard Ballyholme? You should be able to find a curved capo easy enough. Keyser make one. Of course it might be the curve's too curvy. I've got a portuguese mandola like that, but I was able to get a cheap capo with a metal rod in a rubber tube, and it was just a matter of getting it bent to the right curvature.

I've got a Japanese made Angelica guitar, which I think dates back to 1960 or so, and someone told me it was essentially a version of a Harmony. Lovely guitar - nice low action, which I like, and very light to carry for its size. I'm hugging it in this picture. (And if anyone knows more about Angelicas, I'd be interested to find out.)