Dhgate is very good for retro shirts as well as new ones.
The prices are dirt cheap. The shipping takes 1 - 2 months, so if you aren't in a hurry.
I ordered the upcoming Scotland shirt a month ago for £13 with name and numbering... even though it's not even officially been released. Still waiting on it.
Last year I bought 2 retro Scotland tops. One was perfect, the other has a couple of tiny hopes. I received a discount, so it's fine.
Overall, I'd definitely recommend Dhgate. It's so affordable. And it's pretty much made with the same materials, in the same places in China. The only difference is the 600% mark up in price.
Also looking at the classic 92/94 Gold and Green Unitrd top, as well as the home top from the same years.