Southwark Crown Court heard how on 25 January 2014 a family of four were hurrying along a pavement to Catford Station to shelter from a storm when a wall and hoarding was blown onto the father, causing him to lose consciousness and end up hospitalised.
The man, 45, suffered facial and skull injuries including a fractured eye socket and had to have a titanium plate inserted into his left cheek area.
The whole family including the children, four and nine at the time, remain affected by the incident.
An HSE investigation found that GLA Land Property LTD (GLAP) employed a company to manage and maintain the site.
The investigation found that GLAP failed to oversee the contract properly, resulting in the wall not being maintained.
The wall developed a crack which weakened, causing the hoarding to act like a sail in strong winds, eventually leading to its collapse.
GLA Land and Property Ltd of Broadway, London, pleaded guilty to safety breaches and was fined a total of £250,000 and ordered to pay £ £14,653 in costs.
Speaking following the hearing, HSE inspector Ian Shearring said: “A set of simple arrangements to inspect and maintain the wall would have picked up on the imminent danger to any passer-by.
“Instead, a whole family was traumatised by seeing the father sustaining serious injuries from being struck by hoarding as it collapsed.
“It was only a matter of luck that no one was killed on the day outside a busy station.”