Jill Dando was not living at the house she was killed at. It was up for sale.
She was living with her finacee & had returned to the property to collect some clothes.
So any would be killer could not rely on a routine of Jill Dando. Such as her getting home from work at 8pm every night.
CCTV also confirms she was not followed when driving to her property.
So a good chance it was a random killing by George. Or that he knew Dando lived there but never expected to see her. When he did see her, he knew it was now or never.