Sorry for your troubles. My basement shop was the scene of a pipe break once; water everywhere, so I can relate.
I'm probably completely wrong but my experience has been as follows:-1) If water is coming in through the plastic/DPC then one of two issues are present a) There is soil piles up above the top of the plastic allowing water in. If so then remove it and level it to below the floor or b) Inadequate drainage from roofs, or leaking rain water pipe are putting too much water onto the wall. Solution is to fix it.2) Water coming through the wall. Well see the above. You might want to coat the external brick surface with a waterproof sealant. The best solution is to move the rain water away from the wall first.Sorry to hear about your problem and hope they get fixed soon.Al
A quick look at the pictures from the first flood seem to show the following:-1) The damp proof course ( the plastic bit in the bricks) should be at least 6 inches above the wet surface. lets say 2 brick courses. Your pictures show only one brick course so you are too near to the ground. Rain falling hard will often bounce up 4 inches or more. Solution is to drop the outside concrete path by at least 4 inches to stop water ingress.2) I am not familiar with the window structure but it looks like plastic window with a man made seal below it onto the brick soldier course..upright bricks. Is this leaving a space along the mortar joints for water to wick in. If so then change the seal OR arrange the window to have a wooden sill that overhangs the edge of the bricks by at least 2 inches and also has a drip edge underneath.3) Finally after you have made these two adjustments you might want to seal the brick with a waterproofing agent...just spray it on and let it dry.4) your guttering may not be working well enough and might need to be seen to to prevent water running from the roof onto the wall or window.Maybe not what you wanted to hear and I'm sorry for the bad news. It looks a little expensive to fix. Water ingress like this is usually due to poor build methods or poor build quality where not enough attention is made to detail prevention of water ingress.Almost always water coming through a wall is due to there being a build up of the ground on the outside face.good luckAl
Thanks for the comments and suggestions. The mortar gaps around the windows have been sealed with silcone. Mud and leaves are cleaned from the gutters and linings. As the place is a rental I'm not going to invest heavily in the problem. It is a great example of the quick and easy route is usually the long and awkward path.