Yeah, what Jes said. Just identify any hazards and think of sensible actions to reduce the risk. If public are around, suggest signs and observers to warn people what is going on. If roads or structures are nearby think about keeping your distance etc.
A risk assessment is just to show you have thought of the risks involved. Mostly they won't even look at the stuff you send them but they have to ask for it to tick their little boxes.
Any help?