Vauxhall Zafira swooshing of liquid noise when braking, changing gear

look under the bonnet near the windscreen incase the drain is blocked under the wipers also check th bottoms of the doors when you open them

Think it may be water between the flooring and floor pan. There is a 3-4 cm gap filled with sponge. My car had so much water collected there that I got over 10 litres of water out. I could hear the swooshing sound when making any change in movement. When parking on steep inclines a puddle appeared in the carpet. Try removing the floor blank by the drivers side & check for moisure. No idea how it got there or how to dry out.