On one side of my window, the blackout blind cord was too short by 1.5 mm; I had to yank very hard on the cord to stretch it to allow the tab to finally be inserted. Installation of replacement window seal and 'filter'. It should be included in the refitting instructions that: the securing arm (held by two screws) will sit perfectly flat on the seal but, not necessarily exactly over the original screw holes on the wooded panel under the seal. One has to probe with an awl, or suchlike to locate those original screw holes, in order to insert and tighten the screws.
