View attachment 326227 The original rose had an error which is likely why you got it wrong. Also should have been a red or brown sleeve on the line from switch. I personally find trying to wire up a ceiling rose while holding the weight of the lamp hard. I used these
View attachment 326228 ceiling roses so I could wire lamp on the floor then lift up ready wired, it seems this make now discontinued but there are other makes.
The ceiling rose has a duel job in the UK, it acts as a junction box, and holds the lamp up. It means we have un-switched line at the rose handy for emergency lights and ceiling fans, but often as a result no neutral at the switch, so using smart switches is limited to a few makes not needing a neutral at the switch.