Ann: Ceasing to be a substantial holder, page-16

No, i cannot do it myself; that does not mean it is not possible:
http://asic.gov.au/Reports/Daily/2018/02/RR20180219-001-SSDailyAggShortPos.csv
Proved it is possible.

I do not know what's with the 20 mil TBH, I merely wanted to discuss/find out.

It was available via daily short sale report on ASX on 28 Feb.

If you care to read those ASIC RGs, being short may not be simply shorting a stock..