I saw one of these trees at Perth Zoo the other day and then a customer came into my work with the flowers from one. None of the other horticulturists knew what the plant was at the zoo (and I was among some knowledgeable ones), but I am keen to identify it since I have now seen it twice in a week.

It is oddly pinnate and leaves/leaflets are pointed, so I don't think its a Robinia. The racemes seem too long and it is a dark purple.

Any suggestions oh wise ones of the identifying world?!?!

I may need to go back to the zoo and get a proper look as we fairly whooshed past it the other day and it was dusk.