Yes, this is G mellonella. A. grisella is much smaller (18 - 20 mm vs 20 - 40 mm for mellonella). A. grisella is uniform grey brown with the head yellow.
Peters determination is correct, G mellionella resembling a noctuid moth with its strong body and ashen bluish forewings while A grisella has a thin body.
This is correct I can confirm that this is Galleria mellonella. They are both Pyralid moths but the other one is much smaller (larvae and adults). I can't make mistake.