There is draft of cold air coming into the house from my conservatory door.

I have noticed that there is a small plastic part that is broken and has left a hole at the bottom of the door.
I don't know what this part is called.


Could someone tell me what it is called so that I can locate a replacement?

[![hole under the conservatory door][1]][1]

Another long shot to show where this fits.

[![enter image description here][2]][2]


  [1]: https://i.sstatic.net/sPkXq.jpg
  [2]: https://i.sstatic.net/njJpW.jpg