Only 16 years ago JK Rowling was a single mother putting the finishing touches to her first Harry Potter book on a manual typewriter while surviving on benefits in a rented flat in her adopted city of Edinburgh.

Seven best-selling instalments of the boy wizard saga later and accommodation issues are proving much easier to solve for the 45-year-old writer whose personal fortune is estimated at £519m. It emerged yesterday that the author is planning to demolish the five-bedroom house next door to her family mansion in the Scottish capital's plushest suburb in the north of the city in order to enlarge her garden.

Rowling has been on a charm offensive with neighbours to persuade them of the benefits of the plan to level the £1m villa, offering to turn over part of the large plot to a communal space.

One neighbour said locals, who appear to have taken the new arrival in their cul-de-sac to their hearts, were surprised at the scale of the author's plans for the detached period home. She has yet to move into the premises full time which she will eventually share with her husband Neil Murray, who is a doctor, and their three children.

"It's not every day you hear someone seeking approval from their neighbours to flatten a £1m house to make their garden bigger," the resident said after attending a community meeting about the proposal. "There's a lot of respect for her and everything she has achieved through her writing so everyone is happy to work with her," the neighbour added.

A spokesman for the author declined to comment on the plan.

Rowling bought the property 17 months ago for a reported £2m – £1m below the asking price. It signalled her decision to move out of Edinburgh's celebrated "Writers' Row" in the exclusive Bruntsfield area of the city where she lived alongside other leading literary luminaries such as Ian Rankin and Alexander McCall Smith.

Rowling and her husband have applied for planning permission to construct a number of outbuildings in the grounds of the new home including kennels, a summer house and a residence for her security staff. She is reported to have bought two properties adjacent to another of her homes – a 19th-century estate on the banks of the River Tay in Perthshire – in order to safeguard her family's privacy.

The writer also owns a £4.5m Georgian home in Kensington, London.

Yesterday it emerged that the author had given a helping hand to Kate McCann, the mother of the missing eight-year-old, Madeleine, with her account of the disappearance in Portugal four years ago. But Rowling denied reports that she had written the book which is due to be published next month.

In a statement a spokesman for the author said: "While JK Rowling has been a long-term family supporter, her only part in bringing the book to publication has been in supporting the fact that her literary agent was also representing Kate. Beyond this, she has not been involved in any aspect of the writing, editing or publication of the book."