UPDATE:
rang apple yesterday, man said that the rattle was not normal no matter how loud and booked me in for a genius bar appointment. Today i decided to walk around town and go into every single mobile phone shop and ask if they had heard of this "issue", all bar none replied "no", but upon trying their own iphone 4s's they all noticed the rattle as well. Although none were as bad as mine. (so why are the care support so adament this is not normal?). I had to check, because my nearest apple store is 1 hour away and i dont want to turn up only for them to say "it's normal get over it".
So I rang apple support again this afternoon, to explain that i believe the issue is normal, the guy was not having any of it. And advised me to just go to my appointment and get it checked out.
So i thought, right, not getting anywhere, so i rang the actual apple store themselves (the shop, not the support line). I explained the problem, and that i had checked numerous other phones by checking in shops and asking others. He then told me he would be completely honest and then said "The iPhone 4S DOES RATTLE". Although he did say mine sounded worse than the "norm", i.e mine rattles when i move it from my right hand to my left and vice versa obviously, also when i tap the apple logo on the back, also when i place the phone down (even gently).
He told me to come into the store i would most likely get a replacement.
So all this begs the question, if this really is normal, why on earth are the support people sending folks to apple stores and arranging replacements. (and why are they adament that the phones should not rattle).
Just to let all you folks who like me were quite shocked to find out that the phone you just bought under the impression it was a quality "bit of kit" RATTLES!!! it turns out it is normal, but if it is really noticeable, then maybe it isnt.
Dont you just love it when things are conclusive. I mean the guy from the store said "So how bad is it?", and i said "thats the point" I HAVE NO IDEA WHAT BAD IS!!!!