I agree with the previous comment, mile markers were spot on until the 7 mile marker and then consistently long from then on. I feared that the second loop would increase the distance even further but it didn't.
Chimney I've decided to give up on any marathon times until I get to the hundred. So with my current form, I will be on sub-4 until Beddgelert then will fade very badly. Company would be good as the miles go by quicker with somebody to talk too