I'm surprised that the second mark has carried greater influence than the first. While an external marker may not be required on a L6 final project (also unusual imo), it is still possible that a third marker has looked at the work. I think that you have ended up close to the 2/1 1st boundary is unfortunate as it leaves you in the position of wondering if the right thing has been done. In the end, though if the correct procedures have been followed in producing your fyp mark, there are no grounds for appeal. Have you been given adequate feedback on why you were awarded that mark?