Thanks for the welcome.
Yes, I bought all this new when it was first released. I'll dig out the serial number later on when I get back home.
The mouse interface did more than convert mouse signals to up/down/left/right joystick motions. It came with a complete hi-res GUI much like what was available on the Atari ST or Amiga at the time (or maybe it did and hid it very well!) I also had the paint package - can't remember the name but I can find out.
/edit - interesting/completely useless fact: over the 30 years since I bought the Enterprise I've written a metric shitload of software in my day job, and all my error messages start with three asterisks.
/edit2 - you can see a screenshot of the WIMP GUI in the picture, above. It's just under the mouse interface itself on the front cover of the Enterprise Computing International mag.