Interestingly, the reverse is true! No electrical pond equipment should be supplied with plugs fitted. Pumps, UVs, Filters etc should be hard-wired into an earth leakage circuit breaker whereas a moulded plug might mislead the consumer into fitting the device onto a standard socket on the ring main, which is potentially very dangerous. If in any doubt, ALWAYS consult a qualified electrician. It's a pity we received a 3 star review for doing the right thing (!) but hopefully this explanation will help others.
Andy @ Water Garden Ltd.