Hi Steph and welcome to the forum!
I guess it depends on a few factors - firstly are there any washing facilities where you are camping or is it fairly basic camping? How many are you likely to need in total while you are away?
I went glamping with Louis and what I did was take pockets (mainly fuzzis I seem to remember as they dry so quickly) and then extra inserts. If it was just a wee I just hand washed and hung insert and pocket straight out to dry in the sun. The insert was dry very quickly (ready for next change usually) and I made sure I took my thinest/quickest drying tri-fold inserts which were dry pretty quickly as well. I think I tok about 10 in total and that was more than enough. We were away for 3 nights / 4 days and all I ended up with for the trip home was the 3 night nappies and a couple of pooey (rinsed) pockets and inserts. This worked really well however
it was the south of France so I'm not sure if this genius plan would work in the UK!
I've always been very relaxed about using dispos occasionally - I believe they do have their place and if taking them will help you to have 3 days that are more relaxing with less stress than worrying about if you have enough cloth / what if it rains etc.
Have fun whatever you decide to do