Hi djleeg, I am very, very late to your post, but how did it go with Independiente? Also, as you are from the UK, you can just send your music to yourself by registered post. Make sure you don't open it and make sure the post office puts a very clear date/post stamp on your package. This may come in handy for copyrighting existing and future tracks of yours. Oh, and you must state clearly on the package, what track is in it. Sounds obvious but it is easy to overlook.
And gypsyskie is right. Copyrighting your stuff in the USA is a good idea. There is a fee, I think you can do the whole album for $30 or so for the sound recordings. If you want to copyright your album artwork it's another fee. Seeing as people can hear your stuff all over the world, it is a good idea to secure copyrights in the US and the UK. I may be wrong, but I think so.
The US don't accept send yourself registered mail as a valid copyright so do both.
Tell us how it's all going!

You're great.