Turnbull are a class act, the reigning masters as far as I can see.
However, they are also human, and do at times, make mistakes. I have a friend who got one. And, he's not unhappy with Turnbull, and has bought one of their restorations, since.
He ordered one of their "1918" 1911s. This was not a restored gun, but the excellent reproduction they produce. When he got it (2013), I saw it, beautiful finish, flawless execution, fully period correct, except the markings.
The slide did not have the period correct markings, which it was supposed to have. It was blank in those spots. Called Turnbull, they gave him a pickup number, and he shipped it off. Returned 3 days later, all perfect in appearance. All costs paid for by Turnbull.
Now, my friend didn't shoot that gun much, he fired a couple of mags, went in the safe for a while, fired another a year or so later, and it wasn't until May this year that he (actually I) discovered another issue with that gun. It would not eject a loaded ball round.
My friend had fired several mags, but always shot to slide lock, then reloaded, and fired the gun empty. He uses snap caps for function testing, and it ejected them just fine.
I took a look and it had the wrong ejector in it. Called Turnbull, shipped on Monday, gun came back on Thursday. Shop manager called him and told him "that should have never happened", etc. Again, they paid all costs.
They made a mistake, and fixed it, fast, and free, I don't see how one can ask for better service.
Since then, he has gotten an 86 Win .45-70 (gun made 1891 ser#55xx) that they restored. It is absolutely beautiful. Says he would do business with them again, if he could afford it!
If I had the money, and a gun worth it, I would use their services. All their work I have ever seen is top shelf, for finish, and they did right when they could have done differently.