[Advice needed] Which NATO strap should I buy ?

TL;DR : All is in the title.

Hi, I'm looking for a new NATO strap and was wondering which brand should I go on. My daily driver is a Seiko SKX007 and as far as today, I wore it with a unbranded one from https://www.esprit-nato.com . I'm a big fan of Military stuff and history so I would like to go with a "Admiral Grey" as it seems to be the "Original" color (yes, I like grey as a color if you're wondering). So after some search on the net I've found that Phoenix Straps is supposed to be the Original UK army supplier : https://www.phoenixstraps.com/ Has anyone tested it ? It's is really the original one ? It's worth to buy ?