Moving it when dormant is certainly the ideal Chrissy. Think I'd opt for autumn as the damper weather but warmer soil will make it easier to establish. It's certainly better here - takes too long for ground to warm up in spring.
I'd still be inclined to prune back a bit though, but if you can prepare the ground well and take a really big rootball, you might find it's not necessary.
It's a lovely shrub Chrissie. I was considering it for a spot in my boundary too, but I'm opting for a tinus because I need an evergreen for screening and for filtering the wind that batters through the garden.
Good luck with moving it
Agree with Fairy. Move after leaf drop.