If you're considering Soy
Alpro doesn't do bad puddings (can get 'em in the tinned fruid aisle), they have a bit of a funny taste, but once you eat a couple its an aquired taste.
Alpro's not bad for plain soy milk, but
So Good Soya has a nicer creamier taste to it.
If you're looking for a good selection of Non-Dairy products you may want to try
Goodness Direct. I've never used them, but a friend of mine has and says they're pretty good. The selection also looks pretty fair and probably better than most grocery stores. They ship to all over the UK mainland...
Good luck!