A Garden Door scrawled in graffiti has sold for more than £400,000 as thousands of Freddie Mercury’s possessions began to be auctioned on Wednesday night, amid criticism by some fans and Brian May.

The Queen frontman left his Kensington home, Garden Lodge, and its contents to his close friend Mary Austin. More than 32 years after his death, Austin is selling the contents at Sotheby’s with some of the proceeds going to charity after the six-day sale.

There were cheers and applause at Sotheby’s Bond Street headquarters when participants waited for the hammer to fall on lot one – the graffiti-daubed Door to the lodge – at a bid of £350,000. With costs, the buyer will have to pay £412,750 for the door.

The door is coated in scribbled tributes to Mercury from fans all over the world in several languages and over several decades. The auction house had estimated it would fetch up to £25,000.

More than 6,000 people watched the sale unfold online, with many expressing dismay at the spectacle of Mercury’s possessions, including his baby grand piano, being auctioned off to the highest bidder.

Many of the early items in the sale were sold at several times more than their catalogue prices. They included a 5cm Fabergé case with a list price of £6,000 to £8,000 which went for £95,250; a Tiffany table lamp at £60,960, six times its asking price; and a 1895 sideboard at £31,760.

A silver snake bangle that Mercury wore in Queen’s Bohemian Rhapsody video was sold for £698,500. It was estimated to go for up to £9,000.

May made it clear he would not be watching.

Writing on Instagram on the eve of the sale, he said: “Tomorrow … Freddie’s most intimate personal effects, and writings that were part of what we shared for so many years, will go under the hammer, to be knocked down to the highest bidder and dispersed for ever. I can’t look. To us, his closest friends and family, it’s too sad.”

Mercury died in 1991 at the age of 45, just 24 hours after confirming in a statement that he had Aids and appealing for his fans to join “the fight against this terrible disease”.

In total, the auction is expected to fetch up to £11m. Part of the money raised will go to the Elton John Aids Foundation but it is unclear how much. Items range in estimated price from up to £3m for the piano to £20 for a china ornament.

Thomas Williams, a Sotheby’s director, told the Guardian: “Masses of people will be in a position to bid for a little piece of Freddie.”

But many of his fans did not agree and expressed their anger over the sale.

“This auction is crazy,” wrote Frederica G on Twitter, “it is an outrage to Freddie, the members of Queen, his family and all of us fans.”

Writing on Instagram, Cheryl said: “It’s too bad some of these items couldn’t be in a museum where we all could see. Things will be lost for ever.”

In another post, MaryF said: “It’s sad, even painful thinking about all the objects that Freddie particularly loved going to other’s houses – in a blink of an eye. I would have loved a museum exhibition, like at the V&A.”

Auctioneer Oliver Barker, chair of Sotheby’s Europe, said the month-long exhibition of the items on sale had “caught everybody’s imaginations”.

At the start of the auction, he said: “What we’ve witnessed here at Sotheby’s these last few weeks is nothing short of phenomenal. It has captured the hearts and minds of the public all over the world. By the time the doors closed yesterday, on this once in a lifetime exhibition, we welcomed 140,000 visitors.”