Considering that in UK if you live in a building, the door next to you can have a different postcode, I wouldn't worry at all

I've lived in a one bed apartment where the front and back doors had different postcodes.

IIRC, the neighbours to one side in the same building had a third postcode for their front, but shared mine for the back.

If that weren't true, you'd have entire cities in the same postcode. There has to be a boundary somewhere.

Well, in Italy postcodes define city areas, and cities, for example for my city the main postcode is 80100, but my area is 80142, and it contains few buildings, so it's different from UK, UK was the first time I saw such specific postcodes, and I've lived also in Germany and Netherlands

Netherlands had a postcode per street

Oh yeah, I remember being able to insert just postcode and street number in forms, but it's not as specific as UK, I think

Odd numbered homes on one side of the street and evens on the other often have different postcodes

Many buildings also have their own postcode! (The second half of the postcode represents the 'delivery point' which is basically limited by the amount of post that the postman/woman can physically carry...)

Postcodes are about sorting mail to match the delivery rounds.

Crucially, it doesn't have people's names in it.

Indeed.

If it's an issue that someone would know your address, then it's an issue that they would know your postcode.

If it's an issue that someone would know your postcode, then it's an issue that they would know your address.

I'm struggling to think of a scenario where you'd be fine with someone knowing one of those pieces of information without knowing the other.

It's not therefore an issue that there's a lookup between the two. Indeed you can do it trivially with google maps, or the plenty of other services that expose this database through their operation.

Any safety concerns aren't at the layer of translation between postcode and address, they're how someone tied either of those pieces of information to a given person.