Kangoo 1500 dci oil in water bottle

[magooagain]

As above pure engine oil is in the coolant water bottle oozing out of the cap. But no sign of creamy grunge on inside of filler cap or dip stick.
It's seems that somehow oil is getting into the water coolant system but not vice versa.
Head gasket?
Has anyone got any idea what I has gone wrong?

[magooagain]

Thanks for the info. It's the path I have taken. Car is stripped out and flushed and cleaned. Just waiting for the part.
Fingers crossed it's the solution.
Thanks again.