Hi Pete,
I'm sticking with my opinion re Hollyoak and it's been backed up by several experts I've shown the pics to.  Don't forget that it goes through different stages of growth including small holly shaped leaves, acorns and berries all of which can be present on an established plant at the same time but not on newly emerged ones.  Re Corner 24:-  Difficult to find info on it but I did find this "Mode of action Selective contact herbicide, absorbed more readily by the foliage (and especially the shoots) than by the roots, with very little translocation."  This would explain why the foliage is dying but not the roots.  Most people use Glyphosate for general weed killing.