Where is the pcv in a Vauxhall zafira?

PCV normally means "Positive Crankcase Ventilation (Valve)."

Assuming that is the PCV you refer to, it is an integral part the the rocker/camshaft cover, and is part of the plastic/metal cover that is the top part of the engine, (rather than the removable plastic cover that is there to make it look nice) on most if not all Vauxhalls.

If it is making an annoying whistle noise it is not doing any harm, and as such is up to the owner to pay to replace, as it is annoying rather than dangerous or environmentally harmful.