I'll 3rd what Dan said. We have this exact issue on our 2012 in 1 plug hole.  Pops a code and causes rough running from time to time.
It's an o-ring that's leaking.

I'll replace sometime this summer when I get a "roundtuit"

I second what Dan Moffet said, it's almost definitely a bad seal on the valve cover gasket somewhere.  I had the same problem with my Cooper S, and the seals around the spark plug holes were all leaking.

His pic shows a NEW Mini (Bini) individual ignition coil, not a classic Mini coil.

The ignition coils go down through the valve cover to get to the top of the spark plugs. The inside of the valve cover is bathed in oil for the cam shafts etc. There is/should be a seal to keep oil from getting into the spark plug hole. You need to remove the  valve cover and replace all the seals.
 Depending on the type of engine your car has, the valve cover seal could be all one piece, as on the left in the photo or have separate spark plug seals as on the right. (You need to know exactly which engine you have.)

The coil is leaking, its filled with oil for cooling.

Went to change the spark plugs today and there is oil all over the ignition coil. Has anyone had this problem before? Thinking maybe a bad valve cover gasket and spark plug seal? Any ideas on where to start?

Thanks!