One bit of advice I've been given is never to use a bell when alerting a horse rider to your presence. Always talk to the rider. I've been told that this enables the horse to recognise that there is actually a person on the bike, and that bells may make the horse go nuts. Whether this is true I don't know, but I'm rather afraid of horses and suspect that they are not too keen on me. I always try to get a "lovely weather" type conversation with the rider, in the hope that this will make the horse think that me and the rider are old mates, and thus be less likely to try to kill me. It has worked so far.