Gas Hob - how can I reduce the 'minimum' flame setting?

I have a NEFF gas hob, the problem is that even when the gas control knob is at the preset minimum position - the flame is too large and hot. I can achieve a small flame - but I have to carefully turn the knob to a position between maximum and off, not ideal or safe. Is there any way to reduce the gas flow to everything. I have checked - the regulator is new and the jets are correct for propane use.