Yes this is probably what you need, a serviced pitch normally has 240 v hook up, water suply and can also have a drain for the waste. The brochures normally tell you what is included.
Yes as long as you have an Aquaroll, and I think they only fit the 40 litre one, if you have a Whale Aquasource inlet on your caravan, you can do away with the Aquaroll and use one of these.