Use a cake skewer to see if it's done - it should come out clean.
You can store this in the fridge due to the fresh fruit in the sponge and on top, but if its a really cold day I would keep it outside the fridge as it could dry out.
If you struggle with chocolate in buttercream, add 1-2tbsp of whole milk to smooth it out, but only do this IF it has split.
Sometimes the raspberries can sink... and it's not the end of the world. It happens. You can try coating them in a couple tablespoons of flour, if you wish.
Loaf cakes can sometimes take slightly longer to bake in some ovens (if the oven temp is off) as they act similarly to bundt cakes!
If you find your cake is a little greasy, it's most like the chocolate that's melted and started to react during baking - don't worry, you can just pat it off - it won't affect the cake at all, just the outside of it can feel a little greasy.