You could do it now, if you're quick.

Hi, if it isn't wanted where it is, I wouldn't try to move it, at that size it will have a fair sized rootball, which you would have to break most of to get it out of the ground, if it were mine I think I would just dig it all out, and if I particularly wanted a Buddleja where he's thinking of moving it too, I would buy a new one,
If on the other hand it's simply too big where it is, I would cut it back to about 2ft high in mid march, and see what it looks like when it regrows, because it sounds as if it's been neglected for it to get to that height, and all the flowers will be at that height, so not much use really, if you want to, you can cut it right back to 6-9" it will still come back, they're as tough as old boots, Derek.

Buddleas root easily so try taking some cuttings.

Hi, I have a few Buddleja Lochinch shrubs. This variety is scented, has grey leaves and lilac flowers. The most common one is the Buddleja Davidii with purple coloured flowers and greener leaves.
However, butterflies love any Buddleja.

As you mentioned "new house" - I'm assuming that you haven't seen the shrub in flower yet. My suggestion is to cut the shrub back early March when new growth can be seen. You can prune it hard to the lowest 1 or 2 buds. If there are many branches - take some out. The shrub loves a good haircut.

The shrub also produces seedlings freely, so maybe a walk round the garden could result in spotting a young plant. Your problem would then be solved, moving a 'youngster' is easier.

Thankyou all my son appreciates your comments.