For those of us who don't pay for advanced trading tools, you...

For those of us who don't pay for advanced trading tools, you can get the top 20 by going to the most recent annual or half yearly report. Scroll through the doc and it'll have what you're looking for.

It's not perfect, but if a substantial holder (5% or greater) has changed their holding since the report it will have to have been announced to the market.

Hope this helps.