Gable end concrete poured walls rain getting in

[ammm]

have a huge problem with rainwater leaking into the cavity the house is made from poured concrete slabs which seem like they are jointed in some way and has a pebble dash finish on the outside have had a new roof done and also treated the outside pebble dash surface with 2 coats sandtex masonry paint and recently a coat of dulux stormdry which is said to penetrate up to 12'5 mm and protect from water penetration the water is making it's way on the inside of the outside wall it's definitely rainwater because it only happens when it rains any ideas much appreciated sorry for waffling trying to give as much as possible