@bjdmum --Thank you Rona , they started off as pot plants - but grew too big and were turned out to a sheltered corner of the garden --many years ago -- and now are big and strong !!
@pyrrhula -- This plant is a Cordyline --I believe it to be Cordyline Australis -- grown mainly in the southern hemisphere but is in the milder coastal areas of the UK .Mine is planted in a sheltered S-SE corner of the garden .It started life as a pot plant approx. 20 yrs ago got too big and I planted it in the garden .. One bad winter approx 10yrs ago it died in the frost and I cut it down and in a couple of years a new shoots appeared from the sides of the cut stem I selected the strongest and cut off the weaker shoots and this one has grown to this size !!