rrRobbo, I think you have the 4 hint words and have deduced the 4 related words of equal length (to each other). From there I thought that a musical link was obvious, and wrote the related words down in sequence of the four hint words, then translated them into their note equivalents. I ended up with GCDE. Then the 4 X 4 number codons from the down clues should be applied to that : for example if the first codon was 4321, then the result is EDCG. Do that 4 times and use the results for a google search.