Gap under external door.

[AudioDave]

Hi all.

Our external door has a draft on one side, this is due to the seals on the underside of the door being damaged when the previous owners let the door drop. I've asked a door parts site for advice, but they think the part fitted is now obsolete.
My question is, where can I find a T gasket that would fit the 4mm slot (been searching all day) or possibly a U or L shaped attachment that I could fit on. Images of current one attached.

Thanks

 

[Mr Chibs]

I presume you want 4mm wide (not height) brush pile?

Think I’ve had 5mm before, (eBay) think it would be a faff to trim a mm off.

might be easier to replace the aluminium threshold strip on the underside of the door, to accommodate a wider, easier to buy pile.