The Psion II Widget Filemaster v4.5 datapack. This is an exact copy of the software and boots straight into the top level menu. The manual is not included, but is available in pdf format on Jaap’s website (thanks to Jaap Scherphuis).
Free postage on any additional similar datapacks.
In 1992 this software pack was £52.82!

The manual can be downloaded and printed for free from

https://sites.google.com/site/martin2reid/psion-organiser-ii/manuals

or Jaap Scherphuis’ website (jaapsch.net/psion).

Many thanks to Martin Reid and Jaap Scherphuis (and others)!