I have a carbon Fibre front fork "BSC profile design" and when I tighten up all the screws on it snugly there is no movement (forward backward) but I go out for a ride and by the end there is a small amount of slop in it (like when pressing the front brake the fork slides back a few mil before hitting the back of the headtube) is this normal? Or is there something I need to do to reduce the slop?
That's not normal - any knock is also going to accelerate wear so you must fix it soon.
Did you loosen the stem bolts before tightening down the headclamp? See . The tightening order is the same for all materials, but the torques are vastly different. The torque range is usually 4-8 Nm for the head clamp for carbon forks, similar for stem clamps. You can use a special carbon grease to increase friction to that you succeed at low torques. See 
Does it have a couple of years or more of wear on it? Head clamps wear out. Head clamps for carbon frames are remarkably skimpy things.