They've sent you the wrong part then as I got one from them for a 2019 Ceed SW & that fitted OK.
Ok.. remove one end cap ..slide out old rubber. Slide in new rubber.. refit the end cap.. cant get a better view of how the cap is fitted but I'm sure you can work that out.. obviously if your not certain of how it comes out leave well alone..
I currently get my blades from "wiperblades.co.uk" - they are cheap, Bosch or similar, and rapid turnround.What had happened to mine wasn't the actual rubber but the rear blade assembly itself - it was slightly twisted, hence not making great contact in patches on top/bottom & I know why.
The new blade has been through a couple of carwashes and I note it gets pushed down below the rubber on the glass & then pushed back up. Over time I can see this twisting the (very small/short) blade assembly.
As an aside I absolutely hate the rear screen in the Ceed SW (MY2019 on) due to the amount of water/dirt/etc that gets sucked onto it from both above & below when you're travelling at speed.
I understand why its happening (aerodynamics) but its a real PITA to sometimes have to put the heater on the rear screen simply because of water from the road in the middle of May. Never mind having to wash the rear screen more frequently than the front even in dry weather.....
Sorry, we digress.
Try a Niro. Never known a car in all my years of motoring that gets so much crud on the rear screen/boot. Never used rear wash wipe in a car for years. Now I have to as it is the only way to keep screen clear for rear dashcam...As an aside I absolutely hate the rear screen in the Ceed SW (MY2019 on) due to the amount of water/dirt/etc that gets sucked onto it from both above & below when you're travelling at speed.
Sorry, we digress.
They (Kia Parts UK) are actually a Kia dealership based in Hinckley ( New & Used Cars Dealers | Coventry, Leicester & Hinckley | TMS Group ) so how can they not "do" the rear wiper blade? They sent me the right part a few months ago.Checked with them- they don't do the rear wiper blade for 3rd gen of Ceed.