I have had a quick google and if I've got the right place it looks fab! Lots of good advice here, sorry if any of it is repeated.
Take a couple of massive umbrellas and leave just outside the tent, way easier to use if you need to go to the loo block/kettle than putting on coats, especially if warm.
And, if it is warm enough but wet, shorts can be much easier than trousers, as legs can be towelled dry.
A stack of games such as cards, uno etc.
Take a woolly hat and extra socks, you will be surprised how even placing these things on can make a difference to your comfort, and allow you to sit out by the fire for longer.
Firelighters (no one need know
) and marshmallows with wooden kebab sticks, or find some suitable on site. If you do have a fire, fill a bucket of water and leave nearby in case.
Have a supermarket delivery to the campsite. Keep things like tea/coffee to hand. Make sure you have some food which can be heated quickly- instant noodles, soup.
Lots of plastic bags to help when you shower. Also take a few butchers hooks as you can place over doors in showers and tents and hang lots of stuff up.