I was hoping to use these displays in my GCSE coursework but have since decided it would be unnecesarily complicated.  So instead now I hope to use them to make a compass for sailing with; when I get round to it I hope to finish of the prototyping on my breadboard to check I can run the displays.  When they work I will purchase an I2C magnetometer of ebay and will go from there.  My current setup uses 74hc595 8 bit shift registers to drive the displays plus a bunch of uln2803 transistor arrays.  I need to get my Lego Clock transferred to a real circuit board first so I can use the bread boarding wires from that.