I only go to my local, in Beckton, at the weekend, the kids like to see the rabbits and the lizards, and very rarely they got plants left, but I have seen them during the week.
They seem to stock some non aquatics, some crypts, small swords and vallis.
I have not seen Tropica plants on site, the large majority are no brand.
I feel tempted to have a work with the shop manager and see if they would be willing to start stocking plants in better way, but would all depends on economics. 🙂