After the rain last night got a damp patch around the edge one of my double glazed windows, i cant work out why, the window is properly sealed isnt that old, what can i do?, add some more sealent?, put some mortar round edge,or use some of that ronseal weather proofer on the brickwork right next to the cill?. The doesnt seem to be any kind of gap in the mastic/plastic/brickwork