Risk analysis & event management plan

We are a small UK-based charity. In spring of 2024 we will be hosting a sponsored run where participants will run 5km, 10km or a half marathon. The event is to take place in one of London's parks. The event will include a start and finish line, tables in various locations along the route for drinks, snacks at the end, medals etc etc. We need a very simple (but professional looking) risk analysis that takes into account the likely risks of a run, and the risks associated with having a run in a park (dogs, trees etc etc). We also need another simple doc, an event management plan that has timings of start and end, things to consider, what needs to happen at the various stages of the event etc.

Would prefer someone who's done these exact kind of things before, and only those with mid-to-high number of ratings.

Thanks!