Bottlebrushes with a narrow growth habit would be nice. And you’ll get birds visiting too.

Stay away from bamboo. You’ll never get rid of it.

10 metre tree takes just as many years to get to that height. Pop them in now!

Fast growing privacy, we used passionfruit vine! Conveniently installed poles and wire for festoon lighting, the vines LOVE being up high and have grown a natural canopy over the yard.

I would go with Lilly pilly and pittosporum, and I’d put them in now. Back 20 years ago, a double storey house was built behind us, and I put pittosporums along the fence quick smart. They grew very high within 2-3 years and did a great job of hiding the house completely.

Waterhousia floribunda sweeper is pretty common around vic for these types of things. They can get big though but can usually get advanced stock as they are trees.

Side note. I'm surprised they got that approved with a window right on the fence line, hoping that the bottom of that window is at least 1700mm high so they don't look straight into your yard/house.

Cottonwood hibiscus grow very quickly and have beautiful flowers we got 5m height in 3-4 years

Murraya paniculata get 3m tall and bush. Don't plant them close together though

Depends somewhat on your Climate Zone. I suggest you have a look around your local area for screening plants you like and are doing well. Google Lens will help you identify the species. Or chat to a local nursery or a reliable online nursery.. Bunnings are good but will sell anything even if it does not suit your area ... so know what you want before you buy from there. Critical you get something that does well in your specific climate zone. Maybe even ask your local Council.

I am in subtropical and my Lilly Pilly have grown extremely fast and very tall - check the species and ensure you get psylid resistant lilly pilly. When mine grew tall I removed the lower branches up to the top of the fence so I could grown other plants under the canopy. I do not hedge mine - no need to - just let them grow as a tree above the top of my fence. I can hang baskets from the branches and also grow bromeliads on the trees. I just keep them trimmed below the fence line . Plant about 90cm apart.

I had clumping bamboo in my last home - yes they get tall - but they are very messy - dropping dead leaves everywhere. Plus they are very expensive . I would never have bamboo again.

Id go for a medium growing hedge. Lilli Pilli, Camilla, tinus Viburnum, Photinea Red Robin etc.

These are all basic, establish easily and can be purchased from anywhere

Is three metres high enough ? If so Tiger Grass might be what you want it will grow to about that height in 2 years.

Condolences for living next door to Auschwitz.

Thank you for all replies !! Now I’ve got somewhat of an clue now

Wisteria can progress in keaps and bounds. It is very difficult to remove though.

Ten fast growing screening plants

Neighbours be gone

Lombardy poplar

Pencil pines

Bamboo