Aquascaping Stone

[jonnyf84]

where can i get aquarium stone for aquascaping, i live in leeds so it would be better to get it locally so i can actually see it instead of buying over the internet, i've seen a good selection of different stone on aquaessentials but i dont particular want to buy without seeing it first. Has anyone got any ideas where i could collect the stone naturally, rivers, lakes etc.

Any help would be great.