Power and lighting has been mixed for many years as far back as the 2A, 5A and 15A round pin socketsTUT TUT , well its not just about BS7671 is it, come on people remember your days at the local tech college, its about adhering to the electrical craft principles we were all taught.
My tutors would be have a fit if they heard some of the comments going on here.
Practically IMO its not good for a circuit to be running over its CCC even if it only for a few seconds with big loads being plugged in untill its goes pop.
Then you could argue that being plunged in total darkness could warrant a C2 for safety reasons in some certain circumstances.
It would be a C3 for me all day long. We dont mix power with lighting circuits.
A lot of the problem as previously mentioned lies with the lighting manufacturers who insist on supplying lighting kits for under cupboard or plinth lighting with 13A plug in adaptors, personally I would rather they supplied their kits with boxed transformers or drivers with a short flylead that could be terminated into a flex outlet plate or FCU but until that happens I feel we are stuck with what we have