I'm looking in to buy a high mileage DSG Octavia. I came across a very clean 2012 model with 169k miles on the clock. It drove well, there was a full service history, and the cam belt had been changed at 120k. However the service history said that the DSG oil had not been changed at any service (i.e. there were ticks in the "no" column for this service item). Am I right in thinking that this is a 6-speed gearbox with  oil-cooled clutches, so it should have been done four times during its life?

Yes it should be changed at 40k intervals for 6 speed dsg.

Just because it’s not in the book doesn’t mean it hasn’t been done potentially. How does it fee changing gear? 
 

it should be quick almost seemless to change gear. Sports should be even quicker with a blip of the throttle on change down and hold on to the revs going up the gearbox?

 

mine has done 146k and feels really nice and slick but has been serviced throughout its life

It felt fine when driving on a short country test route . Unfortunately given that the rest of the service history is recorded, and it specifically records not changing the DSG oil, I'm pretty sure that it hasn't been done. It's a pity as the car is otherwise in good nick, but fixing a clutch problem is an expensive job that I couldn't take on myself and I don't want to gamble on it. I can't ask the previous owner as it's for sale at a non-specialist car dealer.

9 hours ago, SW- said:

It felt fine when driving on a short country test route . Unfortunately given that the rest of the service history is recorded, and it specifically records not changing the DSG oil, I'm pretty sure that it hasn't been done. It's a pity as the car is otherwise in good nick, but fixing a clutch problem is an expensive job that I couldn't take on myself and I don't want to gamble on it. I can't ask the previous owner as it's for sale at a non-specialist car dealer.

 

You could do what I had to - send all Skoda/VW services an email and see if there's any history of that car being services there. While I'm sure that it must have been done at some stage, If you find no evidence then I'd stay away from it.