Not 100% sure its a head gasket, hydrocarbons in coolant, no crude on filler cap. Engine drives perfectly!
I pose the question as it troubles me, I wouldn't consider placing the car on the classifieds here on this site, however a site such as ebay is an auction site, vehicles are sold as seen. I would have very little issue with forgetting to mention it if I were to Part-Ex the vehicle.
Having owned numerous cars, I'm wise enough to know that sellers don't always confess known issues/faults. Indeed my GTV required £1500 of suspension work to pass an MOT only 2 months after buying from a dealer, they may have been totally ignorant of these faults but I doubt it.
The poll is anonymous, so figured it'd be interesting to pose the question.