I went through a phase of failed scones, and eventually returned to the tried and tested, never fails, Katie Stewart recipe, from the Times recipe book that was one of my formative culinary influences. Here it is converted to metric. The secret of scones is to handle the dough as little as humanly possible, and be particularly gentle rolling it out. Katie also says you have to sprinkle the baking sheet and the top of the scones with flour. No idea what effect this has, but since she says so, I always do it.
Scones are great if you need to suddenly provide afternoon tea, as it only takes 20 minutes or so to make them. They can really only be eaten on the day they are made; they just aren’t the same after they’ve hung around for a while. If you do have leftovers, it’s best to freeze them and then reheat from frozen before serving.