Wouldn't it be cheaper and less risky to lease another one?

If that's not an option, then it's worth finding out whether the DSG on your Octavia Scout is wet-clutch or dry-clutch. If the former, it has a much better chance of lasting several mmore years without trouble.

The DSG on a 2.0 diesel will be wet clutch. We had one in the office that did 150,000 miles with numerous drivers and had no issues.

The oil in these boxes needs changing at the correct intervals otherwise trouble is guaranteed. I would wager that a majority that have issues have not been maintained correctly.

Another problem is remaps. Many VAG diesels are remapped and this can put extra stress on the boxes especially in the lower gears. Not sure about VAG but some manufacturers reduce the available torque to prevent wheelspin and protect the transmission. Many remaps remove the limit feature which is why they feel faster but this will ultimately lead to premature failure.

If the OP's car has been maintained correctly and he intends to continue maintaining it correctly I see no reason why it should not continue to be reliable.

But if he returns it and busy and alternative for similar money what guarantee does he have it will be reliable, in a word NON.

Cost of a new 3 year lease is a similar amount, hence the dilemma...

It is wet clutch.

I do about 12K pa - it's not a case of if it's a suitable car for me, the issue is taking a view on if it is reasonable to expect that it could continue to give good service for a few more years?