Not you Brian!
The cottage has suddenly sprouted Sanderson box window blinds. Not in any room I am likely to occupy but still an abomination. If they are intended to shut out the light, the white ones don't!
The installers insist on wide sills so the blinds can be folded back inside the room. OK so maybe you shouldn't expect to park ornaments or small items on window sills but the expectation that they will fold back neatly to the walls like those on the continent is sadly disappointed. Instead, they droop like Cormorants drying their wings. How long before the grandchildren test their resilience remains to by seen. My comment about 4" nails wasn't well received when the fitter explained that Sandersons don't supply means of safely latching open.
My initial thought, apart from suggesting they take them away, is an inverted cabin hook. Further thought reminded me of threads on modern magnets.
The wider windows have triple blinds, 2 folding and opening one way and
1 the other. A white painted disc magnet and keeper would latch the double together and a further magnet/keeper pair could hold them tight to the wall. Huge strength not needed. (these things are flimsy!)Any recommendations?