The injector seals don't leak diesel when they go, they just sound like a steam train as the combustion blows past. The return pipes do leak diesel. People usually put the clips in the wrong way round because it's easier, but they are designed to fit from the cylinder head side. See this a lot with 1.8's as well. I've never had to recut the injector seat and I've never had one come back. I think the 1.4 is a cracking engine. The only thing we've ever had go wrong with them is injector seals and return pipes,and none have returned after being fixed.