Panasonic NH-P80S1 Heat Pump Dryer – rumbling noise

I have the above-mentioned tumble dryer. Over recent months it has become very noisy in use, inconveniently after the six year warranty has run out.

The noise seems to be something rotational, perhaps a worn bearing or roller, because it has a pulsating rumbling noise. Though an oddity is that the unusual noises stop when the remaining time displayed drops to 30 minutes. But this included today, where it then stayed on that 30 for about half an hour so still heating during that time and it is not a cool down phase.

Given this quieter end period, any ideas of what is best to look at first? I am willing to the take the top, back and sides off and replace any mechanical parts if needed. Though I would not touch the heat pump side of things and it might not be a cost effective repair if it needs parts and a specialist repairer for that side of things.

Thanks,
James