I used a 23cm cake tin and made it as follows;
Melt 165 g butter with 3 tbsp of golden syrup, 1 1/2 tbsp of sugar, 3 tbsp of cocoa powder. Add 340g of crushed digestive biscuits (rich tea’s are a good alternative) and 75 g of dried fruits (raisins, currants, sultanas, glacé cherries – whatever you have to hand).
Squish into the lined cake tin and press down until flattish. Melt 300g of chocolate and spread over the top. I got a bit adventurous at this point and used 100g each of dark, milk and white chocolate which I blobbed all over the biscuit and ran through with a skewer.
Place in the refrigerator over night (or as long as you can stand) then turn out, cut into squares and eat!