I dont mean to be putting anyone off but driving, and not using the park and ride may cause mre headaches than its worth – getting into or out of southend on a normal saturday with the sun up can literally take hours, unless youre planning on getting here dead early (pre 8am) I really think you could end up missing the races.
If you do you are proberbly better off going through to Southend or even shoebury parking there and getting the train back to hadleigh.
Im still in two minds about biking in just becasue it means carrying shoes and helmets with me, will prob jump on the train to leigh and walk or get the shuttle.