Need a quick bit of advice...............

In our house, we've got an extension, and for some reason, lost all power to the extension end of the house.......

Everything on the originsl ring main works fine, and all the plug sockets show power at the live terminals.

Now I'm fine with 12v car stuff, but not too hot on single phase stuff, so would it be possible that there is a break somewhere on the neutral loop?

If so, is there any easy way to check - we have shit loads of plug sockets in the house too.