To local residents who live in caravan parks, you can of course continue to do so. The closure of caravan parks is an instruction for leisure parks e.g. coastal resorts.
Hotels, B&Bs and other types of accommodation can continue to serve key workers (e.g. NHS staff) and to assist those unable to go to a primary residence (e.g. people who have recently been flooded out of their homes and the homeless).
Further guidance on what businesses should close can be found here.