I have done some investigation.

Rattle 1 for me comes from the engine under acceleration. It's in a similar band of revs to where the waste gate rattle can be found in mk6 GTIs and 1.4tsi mk7s but it's not the waste gate. It's more faint than that. The dealer said it was normal when running in (I'm only at 1,300kms). Brendan A had it too and it went away

Rattle 2 for me comes from the soundaktor. It has only started recently and happens in a similar rev band to rattle 1 and now masks rattle 1.

Rattle 3 is very faint and sounds like it's coming from the drivers side A pillar or behind the instrument cluster. It's obvious on rough surfaces when coasting (as opposed to rattles 1 and 2 which are under acceleration).

Rattle 2 is the only one where I am certain of the cause so the car is going in for that and hopefully 1 and/or 3 can be replicated too. It's worth noting that I can't hear 1 or 3 if the radio is on so they're pretty faint.