I would say that Buddleia is too vigorous to be in a container as it possibly pot-bound and will probably need to be watered every day as much of the compost has been displaced by the roots. Better by far to reduce the size by half and plant in the garden with the root ball intact.

Ah, thank you. I never thought of that. Do you know if it would be ok to do that now please? Thanks very much.

As said, lay the pot on its side and try and remove the plant with as much soil with the rootball intact. If it doesn't release the whole rootball due to the shape of the container, then try and cut around the rootball with a long kitchen knife. You can then tease the outside roots out gently. Then just plant the whole thing just the same as any other shrub that you might buy from a garden centre.

OK. Tank you for your help it’s much appreciated😁

Totally agree. They make a large shrub and will come to nothing in that little pot. (Unless its one of the newer miniature ones?) It doesn't look very healthy anyway and is starving.