as and when the office shifts, just inform DIAC, as for physical verification is concerned, you have no option but if you provide enough documents at times they dont do it, the verification is done only when they are not very happy with documents provided. Coming from PK you do not much option. Dont worry about all this, certain things are not in your hands and i am sure even DIAC understands how it is when someone is working and if the company is told this verification is because XYZ employee has applied for a visa, how the person will be treated after the verification.