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S plan+, three 2 port zone valve is the easiest. Think you can do it with 3 port and 2 port but need a separate relay, Only heard of it once and the electrician sorted it. Its not quite the same on unvented, as the 2 port is wired directly to the vessels overheat stat, not interlocked with the boiler.
i was under the impression it had to interlock with the heat source