Sparrowhawk?
Or at least I can't think what else it was - chasing a smaller bird up the hedge at the end of my road. I have suspected that I've been buzzed by one before in the alley up the side of my house but this was a good sighting - for sure a bird of prey and not a kestrel/buzzard or red kite so I think I may be right. Will keep eyes peeled for further sightings. Over and out.