I've started to notice some noise (regular droning, drumming noise) and a bit of vibration with a lumpy tick over at idle. Once you rev up it goes away. Its not bad and I don't think you'd notice if you didn't know the car, but It's definitely there. Any Ideas?

Mileage?

 

Has the DMF been replaced in the past? My first bet will be on the DMF

70k miles and it hasn't been replaced. Reading up on a few other DMF It does sound likely but 70k doesn't seem a lot.

It could be the clutch pulley on the alternator. 

 

I had exactly the same, even after a dmf change.

 

Changing the pulley got rid of the problem.

 

https://www.gatestechzone.com/en/problem-diagnosis/accessory-drive-system/oap-function-tests

 

Thanks it’s up for a service next month so I’ll ask them to have a look.