Perhaps you could ask Dave to split your posts off Neil, it's lost here.
Magnolia Susan is most likely, I have it. The petals are usually paler inside but the shape and outer colour is spot on, your photos are taken from underneath so the insides can't really be seen. The other similar widely sold one is Magnolia liliflora Nigra but that has a more purple outer.
Magnolia 'Susan'
A pic I took in 2009 from underneath ..
Berberis darwinii is the other, one I bought but it died.
