After [repairing some damage to a wall](https://diy.stackexchange.com/questions/135851/how-to-fix-damaged-wall-after-peeling-off-hook), I need to re-paint the repaired area to match the rest of the wall.

I have been given the wrong colour by a shop assistant and it has made it worse (See photo). The paint he's given me is British Standard white, which looks like cream and not white at all.

The one I got is no good either (pure brilliant white, gloss high sheen), because it's too "shiny" and you can see it's a different colour if you don't look straight at the wall.

[![Wall with patch of visibly different paint](https://i.stack.imgur.com/FKrav.jpg)](https://i.stack.imgur.com/FKrav.jpg)

I was hoping 1) to get some advice on the "gloss" or "sheen" issue (I don't even know what that means), 2) again, how do people figure out which shade of white without having somebody physically there?