One final idea before giving up. Kit Williams also designed the Dragonfly Maze in Bourton on the Water which has a "trail" of clues and the sign for it says "can you reach the goal and discover the golden dragonfly". A maze would tie in with "this goes nowhere" and "false trail again". Still not sure what might be highlighted. One idea I have had for some time is that the consecutive letters fghi are in column 8 and, if highlighted, could represent the letter i, but I have failed to see how that might be relevant.