how much can I prune off this Choisya?

[NotAnEMERGENCY]

This Choisya ternata Sundance is blocking the view from my kitchen of the rest of the border. Its flowers should open very soon so I will be pruning it after they have gone.

How much can I reduce its height and girth without ruining it? It's spread is currently about 1.7m.

They are pretty tough you could remove quite a lot by thinning it out and taking it down to about a half. It will bounce back.

I think you could be quite brutal - I was with the one in my garden - it wasn't growing the direction I wanted it to and was taking over like your one - so I chopped it back last year and this year it's fine and loads of new growth.

Ive literally cut mine down to about 1/2 a foot and seriously thinned it out. Grew back fine and at a rate of knots too.

That sounds promising! I'll have a good go when the flowers have finished...