Peter
Look at this on eBay:
https://www.ebay.co.uk/itm/162438189566
Genuine Ford Focus MK3 N/S Front Door Edge Guard Protector 2050626
You have to buy everything in single units. Including the actual door stop.
I believe you have to strip the whole door when installing them.
i didn’t realise what they were when I ordered the vehicle, I thought they were trying to rip me off with some edge strips.
If your careful not to bump it into a wall, then you’ll be fine. It doesn’t protect you from some idiot opening their door onto yours,
just stick to ordering some clear door edging strip mate