House sales rarely go smoothly, but the purchase of Britain's biggest stately home by a Hong Kong investment group has caused astonishment and outrage. When it was announced Lake House Group would pay more than £8 million (HK$94 million) for historic Wentworth Woodhouse in South Yorkshire it looked like just another marque deal for a Chinese business. But in the week since, anger has grown at the way the sale was handled and questions raised about the future of the 18th century building. Campaigners such as Simon Jenkins, former chairman of the National Trust, have expressed their feelings over the sale. Neither buyers nor the sellers have given further details of the deal or what it will mean for this vital piece of English heritage. Julie Kenny, chairwoman of a charitable trust which had agreed to buy the 365-room Georgian mansion "for the nation" after four years of fundraising believes they were used to "bump up" the price. She has slammed how the deal was done and expressed fears for the future of the building said to have been the inspiration for Pemberley Hall in Jane Austen's Pride and Prejudice . Former architect Clifford Newbold bought the sprawling property for a reported £1.5 million in 1999 with big plans. But in May this year, three weeks after 89-year-old Newbold's death, the home was put up for sale by his sons, Giles and Marcus. The Wentworth Woodhouse Preservation Trust had been in talks with the family since 2011 and, backed by £3.5 million of government money, they raised the £7 million "agreed" with them to buy the mansion and 33 hectares of grounds. In August Kenny believed the deal was done. Now she and many others feel "very let down". "This is a disappointing end to all this and we really don't know what the new owners are going to do with the building," she said. "The Newbold family intimated they would sell it to us just a few months ago. Now we feel as if we have been used as leverage to bump up the price. "This could have been a catalyst for regeneration in the area and would bring in people from all over the world. Now it feels like a lost opportunity. "We spent four years working incredibly hard to raise the £7m and we told the family in August we had the money. We made it clear there was nothing preventing the sale going ahead as soon as they wanted. The next thing we're told is that someone else has made a better offer." The owners face a considerably more expensive challenge: the building needs full refurbishment. The trust put the cost at a conservative £42million, but in truth that figure could be upwards of £60million. Add to that the building, twice as wide as Buckingham Palace with 8km of corridors, is sinking. Sitting above rich coal seams the previous owners made billions from mining; now the old workings have caused subsidence. The matter is subject to legal proceedings. A decision on the claim against the Coal Authority is expected in April, but legal fees alone are estimated at £5million. The history of Wentworth Woodhouse is tied to that of three aristocratic families, the Wentworths, Watsons and Fitzwilliams, including one former British prime minister. The earliest parts of the mansion date back to 1725 and the marble saloon's interiors are considered to be among the finest in Europe. More recently it was a college of physical education and had been repossessed by a bank before the Newbolds snapped it up. Now it is the latest high- profile purchase by Chinese investors picking off "trophy assets" - properties, land and vineyards - across Europe. With its background as a brokerage, there is a suspicion Lake House may be acting on behalf of a third party. In its brief statement on the deal, the company said it was "delighted to be involved with the purchase". Its senior vice-president, Michelle Thomas, declined to comment further. "The buyers say they're prepared to talk about the future of the building with us, but every thing is vague. We have been told they will contact us, but we've heard nothing," Kenny said. "I heard about the potential sale a few weeks ago. Sadly we just couldn't raise any more money. As it stands, it all seems very complex and weird." The Newbold family said they had been assured the property would not fall into further disrepair.