Changing the theme shouldn’t hurt your Seo. It’s very easy to change theme. Just go to appearance /themes/install themes. Then click on upload. Upload your new themec(as a zip file)and activate. Your new theme will probably need configuring . But normally themeforest themes ship with instructions.
Thanks for the comment – you were right it was easy.
Next question what if I have two website that are for a similar target market and I simply want to copy the content from the original website printmyownbook.com to selfpublishbooks.co.uk – do I have to manually go into each page (50+) and copy and paste or is there a much quicker way for lazy people like me :-)
Go to : Tools/Export and export your content from printmyownbook.com. Save the exported file to your computer. Then go to your new website selfpublishbooks.co.uk and go to Tools/import. Then it will prompt you what to import, just select pages (if that’s what you want).