16 amps is an unusual number for a circuit. I'm in the States, not a "Sparky" and definitely not sure about the UK so my opinion is exactly worth the price you pay. I wired my shop with the assistance of a Licensed Electrician neighbor. Here we overshoot supply by about 25% greater to meet code and prevent overloading. So, if you have a demand for 16 amps, a 20 amp circuit should be considered.