I've used a moisturiser with an SPF 15 or above since I was about 14 years old. I have very fair skin with freckles that tends to burn easily and I like to feel protected year round. Once the sun comes out in England I up the protection factor with a separate sunscreen.
I used to use Clarins SPF 40 UV Plus Dayscreen, which was quite nice but at £28 for 30ml, it didn't really inspire me to apply as liberally as you should with a sunscreen. I've also used Clinique Cityblock before, both the tinted and colour free versions, but found I did not really like the texture.
The bottle contains 50ml and the product is formulated for sensitive skin that may be oil prone, which mine tends to be during the summer months. The fluid is lightweight and quite runny and absorbs quickly and easily into the skin. There is no white cast and it feels quite hydrating to me. My make-up applies well over the top and it does not seem to increase oiliness, in fact I'm finding it works quite well as a primer.
Regarding the sun protection qualities it provides broad spectrum UVA and UVB protection due to containing Mexoryl SX and XL filters. It's also non comedogenic and paraben free, according to my bottle.
La Roche-Posay is now available on Boots.com although this product is currently sold out. I bought mine for about 12 euro from Pharmadiscount.com where I also buy Bioderma Crealine cleanser and Embryolisse moisturiser.