Anyone spoken to head office, page-9

I don't think it affects their ability to hold an AGM.

AGMs are governed by the Corporations Act, while trading halts and suspensions come under the ASX listing rules, and the rules don't appear to affect AGMs.

But your question made me curious so I had a look:

http://www.asx.com.au/documents/rules/gn16_trading_halts.pdf

As a side note, Paragraph 4.6 on page 12 which deals with Rule 17.2 caught my attention:

4.6 Ending a Voluntary Suspension

last paragraph:

"If for any reason an entity is not in a position to make the announcement about the event it said would result in the lifting of the suspension within the time limit that it originally anticipated, the entity is expected to make an announcement to inform the market of the reasons for the delay, and the new date by which it expects the suspension to be able to be lifted."

It seems BLK forgot about the bit about 'informing the market of the reasons for the delay'.