This is a silly question, if you don't mind me saying. You need to teach English. The Literacy Framework is a discredited piece of nonsense implicitly imposed on many schools. It never was a mandatory scheme of work. In other words, you can teach English in the manner you deem fit. Now if your school has managed to make the Framework work, fine. But you are the professional here; if you think that unit 3 works better before 1 and 2, then teach it first. If not, don't. Either way, just make sure you teach English the best way to your children and do them proud. I've thrown the Framework out entirely without any damage to my pupils' learning. Go on, be brave: trust your own judgement on this.