Police Ordnance is definately the go-to source now. This spring I wanted a Trijicon mount for my Docter/TA-31F but nobody had any, so I bought theirs.
I called Trijicon, and they say that the reason nobody has the Docter mounts is because Trijicon isn't making any more. They are getting out of Docters because they have developed their own micro red dots. Trijicon will be focusing on their own brand, instead of importing and supporting sights from Germany.
I have had the Trijicon winged mount, and I prefer it to the Police Ordnance mount, because it was less bulky. That said, I had every confidence that the Police Ordnance mount would protect that Docter, because it is pretty substantial up there. They are well made, too. Which is good, because at the $200 mark, they aren't cheap.