Copyright

The theory is that, as soon as you have written something, you own the copyright. You don't have to publish it, even, nor do you have to formally apply for copyright. Here is quite a clear statement of the law as it applies to you http://copyrightservice.co.uk/copyright/p01_uk_copyright_law You may register with the UK Copyright Service, if you wish, but you do not need to. One good way of establishing copyright is, of course, to publish your work, as you have done. Lulu is a well recognised self-publishing company and makes it quite clear that copyright of anything published by them remains with the author. Another way of establishing copyright is to mail yourself a copy of your work and to deposit the unopened and date-stamped envelope with your bank. This method is often used by song writers.

From the way I understand it you have to apply for a copyright in England by contacting a copyrighter. I do know however that if you see your work with someone elses name, if you can prove that you definately did it first and it is your own original idea then you can legally sue them for plagiarism. I shall look up what I can and tell you if I find out anything else about it. Source: I used to work for a firm of Typesetters

From what I understand, your works would be covered under American copyright law because the company is an American company. I know American recognizes British Copyright Laws, not sure if it is reciprocal.