I am fairly confident the result would be,

a, d/h c,d, b

d definately would not be displaced from d/h 3rd, either c,d would dead heat second and b 4th or b and d would d/h 3rd. The other way you could look at it is, does a horse protest against another horse or does a placing protest against another placing i.e 2nd v 1st, if this was the case then d and c would have to go up to d/h second as they share the same placing. Interesting thread someone give Des a call.