Gladys is along
The crossword, solved:
Marchers:
unit, ion;
stag, spa;
spangly;
eozoic;
stoa, lei;
AOL, sort;
el, torte
Bands:
uni (in "Tunisia"), tio (in "action"), nay (in "in a yellow"); cite (in "excitement"), trot (in "Métro, tube"), leas (in "please"), ess (in "processor");
tags (in "Samstag, Sonntag"), plier (in "suppliers"), Oslo (in "too slow"), top (in "Utopia");
Angola (in "mango lassi"), Oz (in "Frozen")
The Heyawake, solved:
I used no strategy for the Heyawake. It was trial and error.
Combining the two puzzles
by superimposition, the shaded squares spell out "Ningaloo Coast":
