UK vs US Copyright

I'm trying to finish up my reprint of Gould's Case for the Sea-Serpent this evening, and after a little investigation realized that I'll only be able to offer US distribution of the title, rather than US/UK as with most of my books. UK copyright is life of author + 70 years, which means this book won't be public domain in the UK until 2018, another ten years. Because it had a US printing in 1934, without copyright renewal, it is public domain here. While my UK sales are trifling, I was expecting to sell at least a few copies over there, so this is a little annoying, but not much I can do about it. (Technically, my books would be "published" in the US, and "printed" in the UK, but I'm too uncertain of legal liability in this instance to take a chance.)

Gould's Loch Ness book would also have the same copyright period in the UK, but it never had a US printing (as far as I know). So, in the US, it won't be in the public domain until 2029, 95 years after publication in the UK. So, we won't be seeing reprints of those (legal ones, at least), unless the Gould estate gives permission.

Similarly, I would love to reprint Gandar-Dower's The Spotted Lion, but it's not in the public domain, and I have no idea how to get hold of his estate.