I have just had my light circuit renewed. As I am interested in DIY I had a look at how it had been routed in the attic. I traced the cable from distribution board to all the upstairs lights where either a junction box or ceiling rose had been used, eventually it ended at the bathroom light. However there is an extension at the back of the house with two rooms. There is only one cable leading out of the attic to the extension (There is no access to the roof space over the extension so the wiring must have been put in as it was being built). This cable is joined to the new circuit with a junction box. This means that one of the lights in the extension must be fed from the other which means there is in effect 2 ends to the circuit (bathroom and extension). I am a bit worried that this may be a problem?