How high can I legally grow privacy trees?

Hi guys.

Recently moved house. I've a laurel hedge outside my kitchen window, beside the generic fence that divides my garden with the adjoining house.

Recently my next door neighbor asked me to keep it trim so that it grows no higher than the fence between our gardens, telling me that it blocks light into her kitchen if it grows any taller.

I duly chopped it back a bit, but it's been playing on my mind since. I had been planning to grow it a little taller so that I don't have to see her granny knickers on the clothes line, and more generally to create some privacy from the overlooking houses behind. I'll choose privacy over light, every time.

Legally, has she any say over how tall I grow vegetation in my own garden?

Thanks