The weather was perfect apart from a keen headwind at times. I find that the course only feels undulating on the 2nd lap! The marshals are great as always. I havent run it for a couple of years and found the finish soooo much better than before except for the hill at 19 which I powerwalked up! Wish a medal had been given. The distance deserved a medal. But is still my favourite 20 mile course.
I've posted this answer on another thread but I used to suffer from the same problem until I started lacing my trainers in a different way. I thread the laces throught the top set of holes near the toes then miss out the next two sets of holes, continuing to lace up on the 4th set of holes nearer the ankle and continuing on. It looks a tad odd and I do get comments as my trainers aren't laced up across the middle of my foot but it really helps.
I used to feel nauseous even sometimes being sick at the end of the races 10 miles + until I started taking a Glucose Gel, just before, during and one at the finish of a long race, but make sure its a diluted one and not a concentrated one as with the concentrated ones you have to drink so much water with it which makes me feel sick anyway.