Re: Well the smoking gang...
A hand held umbrella is apparel rather than a structure. If it's supported by being sat on or stuck into the ground, however, then it is a structure. Even temporary structures are counted - you can search for a government FAQ which asks the question "If I hold a party by invitation to, say a wedding and put a marquee up in my garden, then do the regulations apply?" and the answer is something like "Yes, because it's a structure to which the public have been invited and even if the marquee has roll up walls the law still applies and the tent must display a sign to that effect. If you have employed someone to serve food, drink or other entertainment, even on a voluntary basis, then the area becomes classed as a workplace."
