Micra PCV Filter & Valve
 

I had what i hope was a one off:
started the car and got a back pressure explosion. took the lid off the air filter box and one pipe disconnected from the "evaporation emission carbon canister" that comes from the top of the engine block.

I have looked at the filters and found a little diamond one tucked just under the main air filter is full of oil. (believe it is called the PCV filter)
I have also read to check the PCV valve.

So my question is two fold.

1) where is the PCV valve located so i can check it
2) where can I get a replacement filter, i have looked on line an not found anywhere i can get one to the UK. I have a part number 16565-53j01