I stayed at Whittlebury park Golf Club & Caravan/Camping Site.
15 mins walk to track via footpath.
Massive site, although most pitches are sloping. I should imagine it will hold at least 1000 (yes 1000)caravans/tents. Very few electric hook ups.
Food available at Golf Club, there is a campers bar, and a good local pub with food 10/15mins walk away.
They have a website, or email to;- camping@whittlebury.com