So I've made a complex LED grid and it works but has ghosting in some of the rows.
I've given up trying to work out the reason why, but have noticed that when I touch the SCLK wire, or connect the SCLK wire of the TLC5940 LED driver chip to a pair of scissors, or any big chunk of metal, it also fixes the ghosting (pretty much)
So I'm happy with this solution, but would like to understand what's going on. If i connect it to ground instead, it doesn't work. But i presume the chunk of metal has a grounding effect?