Quick search of the local planning office website
The keeping or storing of a caravan, campervan or boat within the curtilage of a house is exempt from permission provided that there is not more than one caravan, campervan or boat, that it is not so kept or stored for more than 9 months in any year, or occupied as a dwelling while so kept or stored. It should not be used for the storage, display, advertisement or sale of goods or for the purposes of any business.
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Any othe use/duration will require planning.