We did this last year. My friend took his van along with our tent and all our stuff on the Tuesday. He very kindly put up our tent next to his van and then we arrived on the Wednesday morning, parked up and walked down to join them. The campervan fields are massive so I'd recommend using the ‘what3words’ app to help your friends find where you are.
The campervan fields are technically off site so none of you will get wristbands until you go into the site itself on the Wednesday. You’ll need to keep your ticket with you and when you go back after each day you’ll go back through the gate and will be given a paper pass out, which you’ll need to keep alongside your ticket for getting back in the following day