I think they supply some of the Blues too - though the supply contracts are fixed quantities IIRC.
I’m not sure I’m doing this right as on phone but here is link to previous post here: Demise of Dark-Blue Working Shirts: RAFAC options?
There was a deal though a 3rd party to supply licensed MTP in small/Cadet sizes but it seems to have stopped, I think it was Cadet Kit Shop and the maker Helikon-Tex from Poland.