Try again...

"A little reality about the horse rider and the people on bicycles. She was riding on a road that was garlanded with notices saying there was a triathlon coming through at that time on that day. She should not have been there."

Absolute codswallop. The reality is that she had a legal right to be there - posting a notice that some kind of 'event' is taking place in no way precludes other road-users from being on that stretch of road unless there is an official road-closure in place, which there wasn't. And, being there legally, the horse-rider had a right to expect other road users to behave in accordance with the Highway Code - taking part in an 'event' on an open public road does not, in any way absolve competitors from their responsibilities under the Highway Code - in fact, rather the opposite.