I am assuming that the bleed valve in the cylinder cupboard is after the 3 port valve and on the primary cylinder flow circuit?
Might be better to re balance the entire system bleeding each radiator in turn as you go as well as the valve in the cylinder cupboard.
I recommend getting a Gas Safe registered engineer to come and do the repairs. You don't appear to have sufficient knowledge of how the valves operate or to check electrical component supplies. When you are dealing with 230V leave it to the professionals, otherwise you risk death...