"Don't pay for the Grandstand" Dorney Warnings Or Dangers Tip by easyoar
Dorney Warnings and Dangers: 6 reviews and 6 photos
It's not really worth spending the extra money of an grandstand seat. The grandstand is inside the enclosure and costs a fair bit more (£10 if I remember). You can see the grandstand and the enclosure here.
Most people who had purchased tickets for the grandstand seemed to leave it anyway and sit on the grass in the enclosure. If you have a grandstand ticket, you are free to go between the two, enclosure tickets don't get you access to the grandstand.