volumes dropping, nervous nellies, page-2

I think the answer is obvious - the majority of shares have been sold to new parties that do not (either alone or through association)hold a relevant interest in more than 5% of the shares (would trigger a new substantial shareholder notice) or for a current substantial shareholder changing their holding by 1% (note that this is why Oceanwide made an announcement, so some of the M&G shares may have gone to Oceanwide).

I would't be holding out for a prompt response from ASIC or ASX to your query, perhaps they have slightly more useful things to do with their time.