I rumaged through my spares box last night and found I had an old 31.6 seatpost so fitted it and bingo, its a nice snug fit. I'll need to source a decent post as the spares box is usually remnants from years of biking and not suitable for this bike but at least i know the sizing is correct.
Thanks for all the positive comments guys and yes it is the most non subtle paint job I've ever seen. For a guy who usually likes the quiet, unassuming brushed ti look I had to take a deep breath when I bought it.