There are several references regarding 'Princess Diana', but she was not and never has been a 'princess'. A princess is the daughter of a reigning king. When she married Charles, Prince of Wales, she was titled Lady Diana Spencer, Princess of Wales.
The "private plate" registration plate number on the contemporary Mercedes, KVX 757, actually belongs to a British Wolseley first registered in Essex on 20/09/46.
When Diana orders burgers for Hasnat from Burger King, the current logo is seen on the bag instead of the 1995 one.
There's a website address outside a restaurant even though the Internet was not popular in 1995.
When Diana is flying a private jet there's a scene filmed from outside the plane, an Embraer Legacy 450 with Tail Registration number PT-TNN. That aircraft did not exist in 1997 and the registration number is for a Brazilian aircraft.
When Diana is alone playing Beethoven's "Moonlight Sonata", the notes she is playing do not match the pitches we are hearing, and one of the bars contains 5 beats, not the usual 4.