We are QLD based and purchased in QLD with Bankwest. We had to get a JP to sign (witness ID). Our lawyer couldn't do it but they had a JP in the office who could.
I don't know if this applies to you but the paperwork was primarily processed in WA so we made sure to express post documents to meet deadlines, rather then waiting a week through normal post for WA to receive it.
Why couldn't your lawyer witness? Lawyers are prescribed witnesses under schedule 1
http://www.austlii.edu.au/au/legis/qld/consol_act/lta1994109/sch1.html
Perhaps your lawyer wasn't actually a lawyer? I've seen that happen in Sydney, support staff passing themselves off as lawyers.