This is a very old pic of Santa Pod but the roads and access are the same these days:
"A" is the ticket offices where you will queue to get in.
If you follow the blue route that will take you to the start of the queue for the strip by the Pod Shop. I expect the stand to be somewhere around the green arrow.
The yellow is where you queue for the strip and i also pointed out the return road where you pull off the strip and head back to the queue past the main toilet block.
If you have stand passes already for the sunday, the security will point you in the direction of the green arrow or thereabouts.
If you don't have stand passes, they will probably stop you near the public car parks, so try saying you are going up the strip and park up next to the toilet block that is where the blue route is on the map at the top right corner next to a toilet block. Then walk to the stand, get your pass and bring the car on - it's a long walk from the public car park to the stand!
Hope that helps a bit.
I've still got 2 weekend camping tickets (inc stand passes) and a few spare stand passes for the sunday still if anyone wants them.
HM