I've done this race the last 4 years and was gutted not to get in this year. If I had got in I would definitely not do the down and up. Don't believe anyone who tells you its a rite of passage etc. Only do it if you want to lose a few places/minutes and you fancy adding several hundred feet of up and down on to tough 21 mile race. One for a casual training run, perhaps, but not on the day of the race. Lloyd Taggart might do it, but he's one of the top 5 runners in the country. Cheers.