Height in the garden

buy some screening material.

We have a buddleia in front of one front window. about12 ft. now
good for bees and butterflies too.
It grows very fast, but is easy to prune. On a Gardener's World programme last march Monty showed us how to do it
When we first moved in there was a huge pampas grass in front of the other window. we didn't like it - too dark inside. impossible to remove completely but we cut it right down and killed the stump with a special product.
There's a thread about it somewhere.

Ooooh no, not Russian Vine. It's not called the mile a minute plant for nothing. I had a neighbour once with a tree that must have been at least 30 feet high. The Russian vine was at the top and waving at everyone...

Trellis with a well behaved evergreen climber seems a good idea.

A bamboo in a pot?

I would plant holyhocks

I had a similar problem with privacy so had a screen built at right angles to the fence. It had two upright posts at about 8' joined at the top by a horizontal bar beneath which was a piece of trellis .. forming an arch, basically. I trained an evergreen honeysuckle up one side and across the top and a climbing rose up the other side. Would something like that be a possibility?

Trellis with yellow ivy, honeysuckle, Russian vine etc.

I have a small magnolia tree growing in a large pot. At the moment (planted recently) it's about 5ft but it's putting on new growth so I'm assuming it will grow larger and thicker.
Isn't the overlooking bathroom window opaque glass?