Not sure what you want to hear. LR 5 use ACR 8.x, so naturally it will be able to open files from newer cameras. CS5 on the otehr hand is stuck with ACR 6.7 and that's just that.
Because your LR is newer than your PS/ACR version, you should be using Edit in PS with LR Adjustments, rather than Open Anyway, and if you are not being asked that question when you invoke Edit In because you indicated not to ask the question, again, at some point, then you should reset your warning dialogs using the button with the same name in LR Preferences.
Thanks for the information as you say not what I wanted but at least I know that it isn't me although Adobe do list the D70 as a supported camera.