✅ No, we couldn't find enough information regarding Lady Louise Windsor working in the canteen and rejecting her title as Queen Elizabeth's favorite granddaughter on authoritative news outlets. However, here's what we found:

1. Lady Louise Windsor's summer job at a garden centre: According to reports, Lady Louise Windsor has been working at a garden centre, helping out on the tills, greeting customers, and pruning and potting plants. She earned around £6.63 per hour at her summer job (Trust Score: 8/10).

2. Inheritance and royal status: There is no mention of her working in a canteen or rejecting her title as Queen Elizabeth's favorite granddaughter in any of the sources. Instead, it is reported that she inherited Prince Philip's most prized possession and is known as "the queen’s favourite grandchild" (Trust Score: 7/10).

3. Education and future plans: The information about her education and future plans does not mention anything about working in a canteen or rejecting her title (Trust Score: 8/10).

Therefore, the given information may be partially - or fully - inaccurate.