Preheat oven to 180 degrees fan forced, and place rack into middle of oven
Line the base and sides of a 22cm round spring-form cake tin (base measurement) with baking paper, put aside
NB: have the baking paper on the base extend beyond it so you can use that paper to slide the cake off the base of the tin and onto a cooling rack once it is baked
Place 250g fresh blueberries in a colander and lightly rinse with water, do not dry
Place the blueberries into a bowl, sprinkle over 1 tbls flour and lightly stir through the blueberries so that they are well coated with the flour (the water on the blueberries will help the flour stick to them), put aside
Place sugar, oil, eggs, zest, lemon juice and yoghurt into TM bowl and blend 20 seconds / speed 4
Add flour, baking powder and salt and blend 10 seconds / speed 4
Scrape around bowl, add the floured blueberries and mix 10 seconds / reverse / speed 3, lift lid and lightly stir mix around with a spatula to ensure an even distribution of berries
Pour batter into the cake tin, level the top then sprinkle over the last 125g blueberries
Place cake tin into oven and bake for 30 minutes
After this initial 30 minutes, turn oven temperature down to 160 degree fan forced and bake for a further 30 minutes
Finally, open oven door and turn cake tin around and bake for a final 30 minutes, or until the cake is a rich golden colour and a skewer inserted into the centre comes out clean (turning the tin around will help to give it a nice even colour on top of the cake ... if you feel the top of the cake is colouring too much, then place a piece of Alfoil over the top of it during this last 30 minutes)
Remove cake from oven and allow to cool for 15 minutes
Release the sides of the cake tin, then use the extended baking paper on the base to help slide the cake off the base of the tin (still sitting on the baking paper) and onto a cooling rack to cool completely
Once cold, the cake can be carefully lifted and the base baking paper removed
Place onto a serving plate, dust with icing sugar if desired, cut and serve
Cake keeps well at room temperature for three to four days