New build property defects

[Daisy03]

Can anyone advise on a situation. About to exchange on a new build property which should be our forever home. Been to home demonstration and are majorly unhappy with some of the cosmetic finish.
Main issue is door thresholds, they have but in dark varnished timber under each door, this is between light karndean in kitchen and light karndean in hallway, and also between light carpets on upper floors.
The house must have fire doors as it’s a 3 storey house, and there must be a maximum 10mm gap between door and floor, there must be this be this to pass regulations.
what it appears is that doors have been slightly too short to meet so they’ve added in these huge planks to bridge it, and are now stating they can’t be changed.
I’ve added a photo of what it looks like between kitchen and hallway, but really can I insist this is changed? To me it looks terrible and low spec, and they should be replacing the whole door if they have to?

Pay someone to go in and conduct a snagging survey before you exchange - it will be money well spent!

Not sure I would describe that as a "huge plank".

What is the height above the flooring and does the profile of it blend in with the floor with no edge ?

If the edge is abrupt then maybe you could argue it is a trip hazard.

It’s about 5mm and no doesn’t blend in. My argument is mainly the appearance, it looks worse with the carpets

Get the snaggers in. If some build issues are obvious then you can only imagine the ones you're not trained to see.

Lol. When I look at my place there is some bodging in areas that are unseen, and that is in a house built 20 years ago.

God knows what they are like nowadays.

I am fixing them bit by bit but it is taking time.

Personally I would either :
A) Use a router to put a 45 degree chamfer on the threshold, assuming you can get them out easily, and it's solid wood.

B) Replace the threshold with something thinner and a lighter colour, and put a small strip under the door, so the 10mm can be maintained. or

C) Replace the threshold and live with the gap.

I wouldn't wait for the builder to do it, as they will probably make it worse..