Line a tin 20 cm x 30 cm with baking paper.
Place 250 g of the milk chocolate in a bowl with the butter and golden syrup. Melt. I did this in the microwave, 2 x 60 seconds on high, stirring in between each minute.
Place the digestive biscuits in a plastic bag and bash with a rolling pin to crush them.
Stir the digestives into the chocolate mixture. Now wait a minute or two before you add one bag of the Aero bubbles, to stop them melting.
Press this mixture into the lined tin with a wooden spoon.
Melt the remaining 300 g of milk chocolate and pour over the top to fill in any gaps and smooth it over.
Chill in the fridge until set.
Melt the green candy melt buttons and pour over the top, smoothing it over quickly.
Cut the second bag of Aero bubbles in half and scatter over the top to decorate, then press down lightly so they stick to the green layer. Chill again until set.
Cut into pieces and serve!