HP Scanjet 5370C produces double height image and cannot preview

The HP ScanJet 5370C has the following problems:

1. When attempting a preview scan, in xsane, the scan head just buzzes without moving down the platen. Is presumably a motor control issue at whatever resolution the preview is generated at.
2. The generated Colour images are twice the height. A sample image is attached that demonstrates this.

Notes:

• The backend version is 1.0.31. User observes that the double height issue was not present on 1.0.29. I have not verified this myself.
• The settings in xsane required to reproduce the double height issue are: Source=Normal, Mode=Color, Medium="Full Color Range", Resolution=300 (and also 150), any height.
• The image is properly produced, but an additional white image is appended which is the same height as the scanned image.