There is no separate "V2" designation or other version on the Unold site. It lists a standardised model Don Luigi 68815 with a maximum temperature of up to 450 °C and the functions mentioned above.
Info from the homepage hope this helps
We offer various accessories and spare parts for the Don Luigi pizza oven, including gaskets. However, the appropriate gasket is not listed directly in the online shop.
Please contact our customer service directly for spare parts such as gaskets. You can reach us by e-mail at service@unold.de or by telephone on 06205-9418-27, stating the Don Luigi model, so that we can help you quickly.
That's it, it's solved! It was the oven casing. Under the right foot, the sheet metal had a small gap with the underside of the oven. I dismantled it and bent it slightly so that it would fit snugly when screwed in. There's no noise now, apart from the two fans.
Apart from that, they could probably be replaced with slightly quieter fans.
The top fan is used to reduce the temperature at the top of the oven. There's insulation around the interior compartment, but this fan reduces the risk of burning and helps to avoid damaging the electrical cables and lighting.
And under the oven, a second fan cools the control circuit directly. So you need to be careful not to block the air vents under the oven (a bit like a laptop).
The correct temperature range would be 80 - 400°. Thank you very much for pointing this out. We will be happy to pass this on internally to the relevant department and hope that this will be adjusted promptly.
I strongly assume that the 2nd version is the version with a temperature of up to 450 degrees. As the 1st version only managed a temperature of 400 degrees. I confirm that this oven can reach 450 degrees and should therefore be the 2nd version.