Help me with my patio door repair

[whattobuy4]

Hi, I have French doors leading out the back to my patio. Both internally and externally the white square panels are falling off, since 3 months ago. Doors are 7 years old now. Can I repair these?

Does anyone know how I'd go about repairing them. Or do the doors need replacing?

I've attached a picture to show the internal part.

They can replace just the bars, the place that fitted the door would be able to give you a quote, they will be able to match to the existing ones I imagine.
https://www.duration.co.uk/clip-on-a-shaped-astragal-bars.asp

I don't know the place that did the door, the house was bought as a new build and the company who built the house are rubbish for contact/information

Doesn't that come under the 10-year guarantee?