Hi I would like to reply to the post... Do Velux black-out blinds have a design flaw? By Steve__M, June 8, 2012 in Retailers - High Street and On-line Stores Forums but i am unable to find out how to reply hopefully one of the site moderators will be able to move this information to the above post Information: I Have also had the same problem with my Velux blind as the above Steve__M where the plastic has been sawn through by the blind cord. I also agree that this is a design flaw and is the inevitable result of friction between the cord and the weak plastic. after searching for a very long time i have managed to track down the correct replacement part which is available from velux themselves as part number 948445 the part is called "side controller handle rail" and comes in a bag containing both left and right plastic parts two screws and an allen key. the cost is £3.60 with free delivery. https://spareparts.veluxshop.co.uk/?__hstc=241362461.ae50091534e8442643758eba0b581eef.1574422240870.1575492598292.1575823794175.5&__hssc=241362461.1.1575823794175&__hsfp=3873202343 the cord can be replaced with ordenary cord just tie a knot in the ends.