we used wilkinsons shaded area grass seed 2 years ago under a big tree we have on one side of the garden, it took well, and now have a lovely green grass with no patches.
I used B&Q's own a few years back. Started with a brown garden and ended up with a green one, so it's OK!
The finished product quality is not as good as the higher grade varieties (either in feel or look), but unless you want a bowling green for a garden, own brands would be fine.