I came from a Discovery Sport and with one Lab/Spaniel cross (23kg) that had ample room to accommodate my dog, obviously it had more room and because of the more upright rear of the car. My EPace is OK for her but the steep sloping rear hatch window does leave a 'snout mark' on the inside of the window. She likes to look out and sitting tightly to the rear seat her snout is very close, but lying down there is ample room.
Two Labs and it would be a bit of a tight squeeze in the sitting position, best to take them with you where there is one for sale and try it out.