Hello Hugh,
Sorry for the late replay, we are on furniture fairs this months.
Here you get the following answers:
1. Brushed steel.
2. ----||----
3. Seat thickness including nozag, foam and leather arround 80mm.
4. Last year we sold 8000pcs of theese two chairs - i think we will start with 250pcs each after sample.
Regards, Daniel