Thanks Ray and Hack. Doesn't seem that I've got a Preview function on this machine. Going to have to wade thru the instructions again.
It seems that you have the scanner controls set as Full Auto which is the setting suitable for straight scanning of A4 documents but does not cater for cropping to smaller sizes. The Epson scanner controls are actually pretty good and simple. Look to reset to Home or Professional mode.
" Full Auto Mode is sufficient for most scanning jobs especially for a quick scan, however other modes are available that offer more options and user control over the settings and final scanned result.
The Home Mode or Professional Mode is recommended for scanning magazines, newspapers and, for scanners with a Transparency Unit (Film Adapter), for scanning film. These modes can also be used for photos and documents, where editing or more options are required. For products with an ADF, Epson Scan also offers the Office Mode".