I've just received my £5 stone. It is identical to the one I bought around 4 years ago, for near £18 (not Trend, different brand).
My £5 Trend wasn't glued on but it's not as flat as my previous £18 one (which is very flat). That doesn't bother me in the slightest, as far as I'm concerned it's flat enough for Plane and chisel blades .