The recent weather has brought to light a serious drainage issue in our garden. About 4 metres from the house. The patio/flags meets the grass and lawn. The flags slope into a corner. The recent bad weather has made that corner get clogged up and a huge puddle. It's only about 2 metres from the house the big puddle which worries me. The flags are just sat on the soil. If I took the corner flag and one next to it up. Dug to a decent depth. Filled with gravel. Would that help the drainage? Also I would like to put the flags back. So how would I go about that. Gravel and then sand then the flag. Would the sand allow the water to drain through?