If it's not ETM what can it be?

You had a new ETM and it has a yellow label ? ( original ETM has silver label ) you need to take it back to them ... The clock going back to zero is a result of software sometimes , they forgot to put it right after ...

Your 'new' ETM is faulty, take it back.

The clock will often re set when a software download is carried out . The garage should put it right again but obviously didnt notice in your case ... but take the car back let them sort it out for you ...

Any fault codes this time?

Well then they may have not diagnosed the problem but as the throttle position sensor is inside the ETM they're going to have a job to dispute the new one they fitted is faulty.

Before going back to them try disconnecting your battery negative terminal and leaving for a few minutes before reconnecting, then try it. May solve the problem.