Can anyone help me with a query about sunscreen? I've recently started using Clairns double wear serum under my moisturiser and then Ultrasun tinted moisturiser with an spf 50 on top. Is this the right way round or should I start with an spf under the serum? If the spf is underneath the other products should I just use an ordinary tinted moisturiser on top? I'm getting a bit confused here, help needed please.