I've bought plants from Morrisons before, they didn't last long. I think it's really luck of the draw with national retailers with the quality of plant that you get.
If anyone is interested, Morrisons have got large Acers (red and green) and large palms for just £8 each. These are big plants, the sort that cost £30 on QVC. They were flying out this morning when I was there.
CC