The childrens section is brilliant you'll have an ace time. Another vote for the cricket match though not sure mine would have sat through all of it at that age.
I went with a 2yo and 4yo they had a total blast, great little people rides, crafty stuff, sights to see and lots of little stages which weren't so loud and crowded which they loved for smaller bands. Actually we preferred those to the big stages. Straw bale seating and space for the little ones to boogy.
We didn't see any scary costumes or lairy adults, everything was a feast for the eyes, but nothing sinister, didn't go to rave valley of course.
The wild swimming was ace for the kids, mine don't mind cold water and were the youngest ones in there and had fun, so defintely be brave and try that. armbands on, off you go.
The toilets when I have been were in decent shape in the family camping area, so don't be too afraid of being close(ish) to them so you can go from your tent easily. In fact some campers drew the 'short straw' got there late and ended up close to the loos... they were under some trees and the toilets didn't smell, so they had their pick of when to visit the facilities being able to see when it was quiet and also cool tents cos they were in the shade!
Massive tent - no problem, just get there Super early! Go as early as you think you can possibly do and then make it an hour earlier (or chance it but then your stress levels will be higher which isn't what you want). I pitched under a guard tower by the perimeter fence... was great as not encircled by others so quieter and we got pally with guards so felt stuff was safe... but the walkie talkie in the night was audible (didn't bother me). Also, on leaving day, we hung around late and once most cars had gone we pulled the car up beside the fence where we were, threw our gear over and loaded really easily, staff didn't seem to mind.
You can hire barrow trucks for carting your stuff from the car but it is pricey and you don't want to be a minute late bringing it back or you pay another hour, take your own if you can, so much less stressful and makes unloading with little ones fun - they can ride!
Loads of food stalls, good ones too, but you will need loads of money to eat solely at those! We took means to make our own for some, wish we'd done more. You aren't supposed to self cater, but we didn't find our stuff was searched so thoroughly that we couldn't discretely make it so we weren't entirely reliant on the stalls. One camper had a portable tagine stove thing and was doing jackets and all sorts.
We got going early in the day and returned for naps when necessary through the day, the family camping is closer than quiet camping so better for little legs.
In the evening lots of people made their barrow trucks into mobile cots and towed sleeping kids round. We didn't, cos we didn't have one and they wouldn't have slept well so would have been too grumpy to enjoy but we could see it worked for some.