Rattle under acceleration when hot

[Chris Boddum]

Hey guys

When the engine is 110% up to operating temperature. say after half an hour of driving on the motorway, the engine will rattle quite a lot under acceleration. It honestly sounds like the timing chain rattling. Happens between around 2-3k RPM and stops at anything higher. I'll link a clip below. It's kind of hard to hear, but you can tell that it's nearly gone when I gear down at the end of the clip.

What can this be? I've had the chain tightened up and while my mechanic told me that the chain wasn't really stretched, it still helped on some engine vibration and some of the rattling, making me think its' a chain rattle. Do timing chain tensioners go bad on these guys? Do my symptoms sound like something known?

Mk2 Aygo, 2015 with 37k miles.