Thank you for your reply, and sorry for the late response i've been on holiday.
I ended up using this instead https://codepen.io/cmalven/pen/vqbJPM
Content in this situation does need to be duplicated, as if you just move it and the screen has a visible area of 3.5 items and you have 4 you see half of the last item jump from the last position to the beginning. Hope that makes sense.