Patio door insulation strips - The Wood

Hi folks,

Does anyone know where I can source replacement insulation for the patio doors?
I have checked some of the mainstream DIY stores and whilst they stock replacement strips, unfortunately they are not wide enough to create a good seal.

The wooden patio doors have an insert that the white insulation strip slots into, it is also in one piece that covers both the long sides and the top and bottom of each door.

Any help, greatly appreciated.