I have just changed the theme on my site to zenpage and get <div style="background-image: initial; background-attachment: initial; ... appearing after the date in the album info box. How can I get rid of this.

Sorry, what album info box exactly? A link maybe?

http://www.martinpoole.com/zen/
Zenphoto version 1.4.2.2 [9365] (Official Build)

You need to upgrade (you are two versions back). That is a encoding bug that accidently escapes html. (that looks like inline css that Safari adds unwanted if oyu paste text from a website). YOu might need to edit your text however as it might be saved that wrong in the database now.

Have updated to Zenphoto version 1.4.2.4 [10045] (Official Build) but still getting the same and browser is chrome

Did you try changing your text as @crylian suggested ?

Sorry about that all sorted now, still learning my way around