that picture above was just an example of what type of fuse box I have, but now I am home here is an actual picture of it:
The big one in the middle, the white button has a T on it, so I think thats the test button for the RCD???

I have also just measured the voltage at a few plug sockets, here are the results:

Live > Neutral - 235v
Live > Earth - 235v
Earth > Neutral - around 0.5-1v