I'm not 100% certain that it's oil, however it seemed to smell like oil to me.
I know that a lot of the hoses have been replaced, including radiator hoses, intercooler hoses, heater matrix hoses and a coolant system silicon upgrade.
it didn't long ago have a service, maybe a month or two ago. Service included all the belts, tensioners, idlers and pulleys.
Thanks for the reply