It will be of no consolation whatsoever, but I know of a childminder who had so many complaints made against her over the years that it defied belief that she was allowed to continue minding. These ranged from "minor" issues like regularly being over her numbers and how she was with the children (in public), but included not strapping children into her car, and smacking.
Complaints were made by other childminders and parents she minded for. We would tell Ofsted when she would be at any particular place (like toddler group) but, apparently, they were "unable" to investigate that sort of thing. They would ring her up, she'd say that everyone was vindictive, and that was the end of that!!
The smacking issue was raised by several previous parents, and I actually minded one of her ex-mindees - and he told me some sorry tales (I was the first person he had told, and he'd been told not to say anything. Thankfully, he allowed me to tell his parents). Ofsted said that the complaint couldn't continue unless parents involved Social Services or the police!
I also know of several minders who have had "properly vindictive" complaints made against them and, even if they've been agreed as vindictive, they have remained on file. Some of them were really really nasty, but unfounded. A parent is obviously going to think "no smoke without fire". The system stinks.
However, I did have some literature through recently that said that the system was changing and, if I remember correctly, that proven vindictive complaints would not be put onto our inspection reports. They would have to remain "on file", just in case.