Hi all - went to the dealer today. 170km there 170km back.
Codes read, brake discs checked for warping or distortion, bearings checked and rechecked. No issues found.
Front drivers tyre looks to have a slight amount of abnormal wear but still with 4-5mm tread. Garage increased the pressures (2,6 bar) and gave me a complementary M-Sport coffee thermos (filled with hot coffee) for the journey home !
Coffee was great but little improvement to the rumble.
I'll go and find a good tyre place and have them balance the wheels and check the alignment on the car to see if that helps - maybe think about replacing the front two tyres.
Disappointing but not the end of the world.