I have just moved in to a house with guttering downpipes that appear to be quite solidly cemented into the ground, presumably connecting to main drainage below the surface. The downpipes are full to a height of about four feet with moss, causing leakage further up. I'll obviously have to remove and clear the pipes but would prefer them to terminate above ground with a gully (think that's the right word, or maybe 'hopper') with a grille over it to catch debris. I'm not sure how involved it would be to convert them - or if it's even possible. Can anyone advise of the steps involved please?