This type of accident happened to my daughter, she slipped down a slope in the local park - her foot went into a hole and she fell and broke her leg in 2 places. Her partner took photographs the same day, but by the next day, it had been repaired and was not dangerous. She submitted details to the council,and was recommended to fight the claim through her union by colleagues at work, which she did. After sticking to her story, after denial by the council, eventually it was agreed out of court, and she received compensation. Perhaps a phone call to the citizen's advice office may be able to offer you some help but don't expect anything to be sorted out in a hurry!