That's allright Unit,
No, you don't need 10 sq. meters of carpet, Have a look at this photo of a complete set of Cooper carpets laid out aligned with the carpet's grain:
The tiles are 31.5 cm square, it adds up to 5 sq. meters with all the grains aligned.
You can't get Westminster, you get it's modern equivalent which is Tretford carpet(Tretford bought Westminster out).
Same stuff(80 percent goathair), but with a modern PVC backing included for longevity so is 1 or 2 mm thicker, no real drama there. The black carpet which you can see in the photos is a so far unidentified auto upholstery carpet. I got this 2 by 4 meter roll for 20 dollars. If I had 1 roll meter more I could have completed the whole job.
This particular carpet is great in that it is the same thickness as Westminster, is carded (ribbed texture) like the Westminster/ Tretford but is economical and strong. So it's perfect for the average car, and will last as well.
It's also proven to be easily sewable on a domestic machine too!
Have a go, the work is easy, and the result is fantastic. Use a cheap carpet for the first one though. I'll try to get a name and price for this stuff on Tuesday afternoon from Daley's in Parramatta.
I'll even put the dimesions up for the front carpet (as that is the most satisfying one to make) before I leave town this week to get you on your way.