Ovivac and lambivac also cover clostridial disease, but fewer types than heptavac(which also covers pasteurella). Ovipast only covers Pasteurella.
As a vet, I'd recommend covering all of these that you can, as most clostridial disease can cause sudden death or serious life threatening disease that is almost impossible to treat.
I recently started covering my sheep and goats with heptavac p, as I had lost an old tup and an old ewe, which could have been pasteurella, or a clostridial septicaemia, and I wanted to give them as much protection as I can.
It is always an individual decision, particularly following adverse reactions, but as clostridia are in the ground everywhere, every farm has some risk.