So just as an update. Having changed oil and coolant, started up no rattling. After 30/40 mins of riding a very slight rattle though not sure if now I am just listening out for it more. But no idea whether it is resolved. Having read about others who tried to get this addressed under warranty some dealers apparently just did an oil change which solved the rattling temporarily. Will see if it comes back. Got a slot booked in with dealer and will see if I can get a discounted replacement CCT.
And also should say - there was no weird stuff in the oil! My bad - was just rushing too much! Seeing things..(In case someone does have an issue with contaminated oil and comes here looking for solution)