IN CASE you hadn’t noticed, here in the UK, we are in the middle of a blistering heatwave. This gives us an opportunity to revisit which Sun Protection Factor (SPF) product to use (you could hide away in a darkened room, but that isn’t a very realistic option). SPFs can cause a lot of confusion – should I choose a mineral or a chemical one? What is the difference between UVA and UVB rays?