Why do the easy jobs never go smooth... OIL CHANGE WOES

[Oldiebut goodie]

Use a socket on the other end!

[itchyfeet]

Surely easier to buy the right sump plug, not convinced a box spanner would fit anyway.

My guess is they drilled and tapped M16 or they would have reused the old M14 plug.

A Standard M16 plug is no good because you can't get a socket on

M16 suitable for WBX...
https://www.brickwerks.co.uk/sump-plug- ... rsize.html" onclick="window.open(this.href);return false;

[Oldiebut goodie]

A set of box spanners is always handy, usually the wall is a lot thinner than standard sockets. They are also handy for things like bleed nipples so that force is applied evenly each side rather than twisting off which is always happening to people who use a spanner or ordinary socket and applying one sided pressure.