Chocolate Orange Biscuits

Hi Lindsay, made Delia's Orange & Chocolate Biscuits,rolled out dough about 1/4" to 1/2" deep & used 5cm fluted cutter but biscuits were
very thin about 1/8 " deep when baked,
for second batch I took a piece of dough size of large walnut & rolled it between palms of hands & flattened on baking tray-Delia used this method for Ginger oatmeal biscuits on video,
Biscuits still v thin & looked smaller than Delia's,
Biscuits were v sweet didn't get bitter sweet contrast as anticipated, by how much can sugar be reduced? how small can cholocate be chopped, is it ok to do this with serrated knife?
& what width & depth are Delia's bisuits before
Baking. Thanks for help,Frances Therese.