Yes - it is the correct size and the frame is almost new. It is a steel frame with a carbon seatpost. That might be the problem, but I once read (cannot remember where) that this DR-model had this problem - at last many owners had the problem. I will try some FSA Compound.
Alas - I have only had 1 ride on it - very short - the real problem might be that the one building the bike .......greased the carbon post...........Some cleaning first I guess......