Had I delved deeper, I would have realised there is a better way to update a theme.
Don’t use the automatic update
The easiest way to update a theme is to click on the themes tab and click automatic update. As I found out this can lead to problems if the theme update isn’t quite right. The best thing to do is to download the update manually.
Do download manually
Go the the themes tab in your WordPress admin set up and find the theme you want to update. There is usually a link to the authors home page on it. Click this. You can see from the image that the details show a directory path to where the theme resides on your host. This will be useful later on. Once you’ve found the theme authors website, you should download the zip file with the updated theme in it. Once you unzip the download it’s important to perform one check. If the download is in a folder called something like “Theme.3.1”, you should be okay because each new version is given a different name. If it is called something like “Theme”, you should change the folder name to something unique.
What we’re going to do now is FTP the folder up to your hosted webspace. If you used a hosting companies “one click” or “easy install” to set up WordPress in the first place, you might not know how to set up FTP access. Contact your hosts support, they usually have a really good how to article on this.
FTP stands for file transfer protocol but that really doesn’t matter, most modern packages like Filezilla present you with an interface that’s not much different from Windows explorer. After you’ve connected to your webspace you want to navigate to where your themes are kept. This is usually something like (/wp)/wp-content/themes. You should see several folders in there, including one for your current theme. Double check it has a different folder name as you don’t want to over write it with the update!
The clever bit
Once you’ve transferred (FTP’d) the updated theme to the themes directory, it’s time to go back into your WordPress admin page for the themes. You will now see two versions of your theme there, the one you are currently using and a new one which will need activating. Activate the “new” theme. Rather niftily all the settings are kept from the old theme (this is because the settings are kept in the database and not within the theme itself), so you should be up and running immediately.
Play around with the new updated theme, see if it works properly, and if it doesn’t, all you have to do is go back into your theme admin page and reactivate the older version. That’s one heck of a safety net and a big enough bonus to make sure I never click the automatically update button again!