The heater is fine, the only problem is that it is fitted with a control switch knob which shows two heat setting. Being a 3kw heater the knob should show three heat settings.
Dimplex Customer Services' answer is to return the heater as faulty and request a replacement heater as, incredibly, they cannot supply just a switch knob.
That is a lot of unnecessary hassle to correct a very simple fault, it's much easier to keep the heater and write a 3 on the knob.
The heater is worthy of 5 stars, it is let down by poor support from Dimplex Customer Services