On reflection, I think you're taking on a bit much for a first flight after getting your PPL. I always reckon ONE challenge at a time is a good idea. You're going to a new airfield, with your first passenger, in possibly challenging conditions (short day, low sun etc). That's two or three challenges. It means you're likely to be slightly overloaded, with not enough spare capacity if anything goes wrong. I'd suggest doing a local flight, then next time taking up a passenger, then after that going to Duxford....or some version of that anyway.
I had a couple of minor mishaps in the early days, and if I look back, it was always due to trying to run before I could walk very well.
