You are using axis.title = element_text(colour = "#7F3D17")
to get the right color for the title. But you should be using plot.title = element_text(colour = "#7F3D17")
.
With axis.title
you define the setting for both axis, whereas with axis.title.x
or axis.title.y
you define the setting for the x-axis title or y-axis title specifically.
Because you are using the same color for all the titles, you can also use title = element_text(colour = "#7F3D17")
which should set the color of the plot title, axis titles and legend title to the same color.