What is it about Greenfield Crescent, in leafy Donnybrook, Dublin 4, that makes the residents want to tear down their houses and start again? This week, the planning authorities received an application from the owners of Number 3 who are keen to level their house and build two in its place. At the same time, permission was refused to their neighbours at Number 10 who wanted to do the same thing. The owners of that house bought it last year for £617,0000.