So based on previous experience, I need 2.5mm TPS 2C+E for the powerpoints, I've been told I only need 1.5mm for the new light. Can I use the same 1.5mm for the additional switch?
When I ran a cable for my light I think the sparkie said the 1.5mm2 required maximum 5A breaker, so you cant put it on a 10A circuit even though the light doesn't draw much current. Its about the cable being able to handle enough current under a fault to trip the breaker safely. For this reason its probably easier to get 2.5mm2 all around.