Dropped my bike off on Saturday to the Giant main dealer & left it with them , they reported back on Monday after speaking to Giant & said that its most likely the paint cracking , worse case scenario its stress in the carbon , either way they're both covered by warranty & they're sending out a brand new 2017 Defy Advanced 2 Frameset for me , will be here end of October when I'll need to take it back in & all the parts from my old bike will be swapped to the new frame & I'll be re fitted as I was when I originally made the purchase April this year , great service from Giant again , I'll continue to ride the old frame & just monitor the damage around the seat post area for the time being