[Allspeed]

What size does N18 use please? I want to replace the oil shortly and need to make sure I have the tools need.

 

[Oakleyguy]

You may want to get a Dimple magnetic sump plug.
I purchased one for my R56 JCW, absolutely fantastic and will collect any nasty bits of metal in the sump.

https://orranje.co.uk/product/dimple-magnetic-sump-plug-2nd-gen-mini-r55-r56-r57-and-r58