Pendine is hard sand but the tide comes in and out, not fully in but enough to make it damp and slippery. Iv been there many times as it's fairly local to me. There's plenty of room if u do make a mistake but it's very slippery. Top gear use it for messing around on, they never use it for any high speed stuff. Guy Martin used it recently for his push bike world record of 100mph and he found that had bad traction!
As for the sand getting every where, I'm sure iv still got sand on my Capri from 13 years ago when I was down there!