CL Site Hidden Charges

I thought I would post on a topic which may have been covered before but a topic which affected us and is concerning additional charges other than posted in the Caravan Club handbook. I don't know whether I'm being unreasonable but we have just stayed on a CL site which we pre booked for a few days in October. At £15/night with advertised facilities inc. WC, Shower and H&C was enough to pay so we thought. However, when we arrived we learned that there was an additional £5 / caravan to use the shower and toilet which were in the form of Portashower and Portaloos with no lighting. Now I have seen showers offered with a 50p charge / use, but I thought it a bit steep to have to pay £5 to use the toilet / day. Are our expectations too high, or should the CL site vendors have been more transparent about their charges in the CL handbook. So what do you think?