Thanks Rich. I used the PPA under Ubuntu 16.04 but after upgrading to 18.04 I had huge problems with libgimp2.0 and 3.0 dependencies, with GIMP and Xsane conflicting. It may have been unrelated to Gimp but I'm not keen to experiment straight away. If new requirements force a change I'll report back. I'll document the ImageScan workaround in a couple of days.