As you can see, the graphics are very basic, but extremely bold, bright and colourful. The game was published on a disc based magazine called Fast Access in the late 1980s and early 1990s. You were sent six issues a year, on two floppy discs, with some printed cards you put in a special ring binder. I believe two volumes were made, while the third dispensed with the printed cards completely, was spread to three discs, and only got three issues, before it went out with a whimper.
Goldbank came on the second issue of volume 1, about early 1989, so it's pretty vintage. However, the game is a great challenge. Do have a play of it.
Getting to build this disc image using my article was more difficult. The available Fast Access images are served as double density discs. Attempting to use the bbcim utility actually lead me to create corrupted images, which subsequently didn't work.
Fortunately, a comment left by Ant mentioned a set of similar utilities hosted/written by Stephen Harris, this time written in Perl. I had more success with preparing the Goldbank image, so I'll detail below what I had to do, in tandem with bbcim.