I have just had the problem fixed by the lovely Nathan at Epson UK. It's long-winded, but it worked! Here's the e-mail he sent:
Dear Mak
Thank you for contacting EPSON e-mail support.
I would advise trying the following procedure:
1. Close any applications that are open.
2. Click on the Apple icon and choose System Preferences. Choose "Print & Fax".
3. Highlight the Epson printer in the list and click the delete button [-].
4. If no other printers are installed, in Print and Fax please hold down the Control key and then in the list of printers, click and hold. That should present the "Reset printing system..." menu. Choose this option and confirm.
5. Disconnect the printer from the computer.
6. We will now remove the EPSON Printer driver from the system and delete the drivers that you downloaded.
Go to the Mac Hard Drive/Library/Printer and move the complete EPSON folder to the trash. Warning this removes all EPSON Printers.
7. Also remove any drivers that were previously downloaded to the trash if the file name does not match that from our web site.
8. Restart the Mac.
9. Empty the trash.
10. Now we will run a repair utility that may take up to 30 minutes to complete so please plan for this. Go to Mac Hard Drive/Applications/Utilities and open the Disk Utility. Note: If you cannot find it this way, use Spotlight to locate it.
11. Select Disk First Aid at the top of the dialog box.
12. Select the Mac Hard Drive Icon in the left hand pane.
13. Select Repair Permissions at the bottom of the dialog box.
14. When this has completed restart the Mac.
You will now need to download the driver/s from the Epson website. Please connect to the Epson website via the link below:
http://esupport.epson-europe.com/SupportHome.aspx?lng=en-GB
Download the printer driver for your printer and ensure this starts in the Download Manager. Please try the following to install and add the driver:
1. Locate the downloaded file and double-click it. This should mount a drive on the Desktop. Double-click this and a window should appear with a blue VISE icon. This is the printer driver installer, double-click this icon.
2. Follow the on screen prompts to install the driver, restarting the Mac once the installation has been completed then power the printer on.
3. Start the Setup from CD for wireless install and follow on screen instructions.