The period of tenure for each privately owned caravan holiday home will vary from one park to another. When you buy a new home, the licence agreement should have a start and end date clearly defined.
Insurance is very strongly recommended. It may be provided through the park or it may be purchased separately. You should ensure that your belongings are covered, too. Go to the insurance page to find companies that specialise in caravan insurance - note most policies do not cover alternative accommodation if your home is rendered uninhabitable.
Caravan holiday homes must not be used as permanent residences. A holiday park's site licence (and the consumer's licence agreement) will specify that the park is for holiday use only. All residents must have a permanent address elsewhere. Park homes on a residential park can be lived in permanently.