A TV licence covers the named person and anyone living with them at the address stated on the licence document e.g. members of their family. If a person uses television at a second address, they will need to hold a separate licence for that address.
However, there are three exceptions to this rule:
� The use of television in a static caravan (i.e. one that remains �on-site�) will be covered by the licence held for the user�s main address, provided there is no simultaneous use of television at both places
� The use of a television in a touring caravan (i.e. one that is used for touring from place to place) will always be covered by the user�s main home licence
� The use of a television set, which is powered solely by its own internal batteries will be covered for any address by the user�s main home licence. However, if the user plugs the set into the mains or connects it to any external power source such as a car battery, a separate licence would be needed.
http://www.tvlicensing.co.uk/pdfs/40115_BBC_Fr eedom_of_Info.pdf
This means you can use your laptop in the car but not when attached to the cigarette lighter.
Any TV receiving equipment powered by mains electricity used in your office needs a licence for that address.