Acanthus mollis transplant.

Acanthus have very long tap roots and do not generally take to being moved once established although small seedlings move OK (I use this method to pot up some for plant sales). Also, like dandlions, the smallest piece of root regenerates so you will probably not get rid of it in one go (I spent all summer painting systemic weedkiller on emerging leaves of removed plants). Given the method of propogation is by root cuttings, you could try digging one up, taking a few pieces of root as insurance and replanting the rest. Good luck

Andrew is absolutely right - you'll have a job moving them and more little ones will pop up from where you dug! I have great problems keeping mine under control due to the 'babies' it has! Why not start again with babies planted where you want them, then get rid of 'Mummy' plants?