Noise itself is not subjective. Loudness could be considered to be subjective but considering I asked people to compare them with a Gaylander TD4, people were able to provide some insight.
It isn't a daft question. I can't hear in my left ear and when travelling in a noisy car, that can be a nightmare, especially while driving. It can often be difficult or impossible to engage in a conversation with others and that can be really awkward. It all depends on how quiet the car is. Most probably don't even give it a second thought tbh, except chavs who typically like to make as much noise as possible.
The TD4 isn't too bad but when travelling at 70ish, I find it almost impossible to hear people in the back. When I had a BMW, I never had that problem so I definitely wouldn't want anything much noiser than a Gaylander TD4. Ideally I'd like a LHD car but those tend to be stupidly overpriced.