We had our visa granted in October but due to long processing times we have had to get new passports, I understand we have to notify DIAC of changes in passports.

Is the correct form to use "Form 929" ?? which seems to be needed for change of address or passport.

Many thanks.

Do you have your Australian visa sticker in your old passport?

no

In that case, I'm not really sure. I'm surprised they issued you with the visas without the new passport details; we still had well over a year left on ours and the CO requested we get new passports before she issued the visa. Form 929 is the right one to advise them before the visa is issued.

I think I would send them form 929 with a covering note to your caseworker explaining that you've not yet had the sticker put in your passport.