living in a static caravan on a business premises

[countrybumpkin]

my partner and i have to travel daily to my friends business and has asked us if we'd like to move into her static caravan on site for security and help us out.
we just need to know legal implications and how to get permission?

[buildersmate]

There will be a planning issue to be overcome and business rates / council tax issue to be sorted. Apart from that, it is easy.
Planning involves the owner or leasee of the property making a planning application for an amendment to the use to change it from business to mixed use. Which may or may nor be acceptable to the authority - it depends.
That initself (if successful) will trigger the council tax people to get the propertry re-assessed for part business rates, part council tax.