Hi,
I've been in a mad panick all week trying to find a site as my usual camp site, (Southern Leisure Lakeside Village) is fully booked up.
Have a look at
www.sussexlive.co.uk for a list of accomodations.
However Saturday night camping, is the most popular and you will struggle to get in locally.
Ones that I know are fully booked are Southern Leisure Lakeside Village, Ellscott Park,Wicks Farm Holiday Village, and one up at Graftham near Petworth.
Don't know about for the Saturday night, but there was vacancies at a place in Slindon near Arundel for Thursday and Friday but they don't have any toilet or shower facilities. 01243 814387.
I have booked a place at Barnham (Lillies Nursey and Caravan Park) 01243 552081 but don't know of availability for the Saturday.
You can also try the Ship and Anchor Marina at Ford near Arundel 01243 551262
or Nunnington Farm Camping Site at West Wittering, south east of Chichester which appeared to have spaces free when I rang them, but decided to look elsewhere first due to its location and possible traffic problems early morning. 01243 514013
Hope this helps