To help you find the key film locations I've linked them here as a self-guided walking tour starting from Notting Hill Gate tube station. The walk is about 2 miles long and will take under an hour from start to finish.
1. Coronet CinemaAt 103 Notting Hill Gate, next to/opposite Notting Hill Gate tube station (depending on which exit you take) you'll find the Coronet Cinema. This is where William (Hugh Grant) watched Helix, the sci-fi movie short film starring Anna Scott (Julia Roberts).
The Coronet opened in 1898 as a theatre and was such a well-respected venue that King Edward VII saw a performance here and Sir John Gielgud saw his first Shakespeare play at the Coronet. Today it is a popular cinema for the local community and has current releases at better prices than in the West End.