When passing horses one definitely needs to give them extra care.
If they are coming the other way I usually pull in and switch off to let them pass.
Trying to overtake is difficult and I usually hold back but make sure the rider knows I am behind and wait for the wave on. The rider will often pull in a gateway and wave you past but always best to give them extra caution and try to keep the revs down when passing and well beyond afterwards as it could be a particularly nervous horse.
