The Flow frame wont be any use to you, you need to find out where the bees nest is. It could be in the wall between the brickwork & gyprock, or if it’s a 2 story house, they could be between the floor & ceiling between the floor joists. A way to locate the nest is move your hand over the gyprock till you feel a warm patch. If it’s in the ceiling, you certainly need to remove the gyprock to remove the nest. If it’s in the wall, it’s not that important to remove the gyprock. You can lure the bees out with a “trap out” to get as many as you can in a box before shb takes over. Once it is all over, the important thing is to seal any gaps that don’t need to be there & use fly wire in all the weep holes so the building can continue to breathe & not allow any more swarms to move in. When you find the warm patch, you’ll get an idea of how large the hive is by the warm area, also the gyprock will be dull, not drummy between the studs.