Well after reading numerous threads, and lots of peoples reviews on the clay bar, I finally got myself the Meguiars 50g Clay Bar & Detailing Spray kit for £15.
Oh my god is all I gotta say' it is VERY easy to use, and the difference is crazy! Whole car feels smooth as glass, I was so impressed called my mate over to show him the difference, even he was shocked ... and the contaminents you pick up on the bar is amazing, so much contaminents that arent visible to the eye but effects the depth of the paintwork!
Put it this way, I will be claying my car on a regular basis, about 4 times a year, it takes no longer than just over an hour n a half if you chill out and dont rush yourself taking rests in between etc and about half/25g from the tiny 50g bar you get with the meguiars kit was enough to do the car ... next time ill buy the clay seperately so its cheaper.