There is nothing to stop anyone simply placing a caravan in their back garden and
using it as an office or even for overspill sleeping accommodation when relatives
visit (always check with your local planning dept.first).
Aesthetically this is probably not the preferred view from your windows though, add
to this the fact that these caravans, although quite roomy, are designed to provide
short term family accommodation during the summer months.
They are constructed of sheet aluminium with single glazed windows and tend to be very hot in summer and bitterly cold in Winter with major condensation problems
Fortunately these problems are easily resolved, the first thing to do is to get rid of the huge metal picture window at the front.This is draughty and unnecessary for office use, it can be replaced with a standard timber or UPVC window.In our situation the small window to the side was not required either.