Fatima and Eskandar Maleki have reduced the asking price of their Mayfair property as high financing costs and political risks sap demand for luxury London homes.

The five-story Edwardian mansion, which is nestled between Hyde Park and Berkeley Square, is now listed at £30 million ($36.5 million), down from £35 million, according to people familiar with the matter.

The reduction is the latest development in what has become a prolonged sale process for Fatima Maleki, an art collector and Tate Modern donor who is named as the property owner on a Land Registry filing, and her husband Eskandar, once the largest individual shareholder of energy producer Tullow Oil Plc and a member of Mexican energy developer Renaissance Oil Corp.’s board of directors.

Since listing the mansion about three years ago for £40 million, the Iranian-born couple have struggled to find a buyer, the people said. The couple have lived abroad since becoming exiles during the Islamic revolution in the late 1970s, according to a New York Times interview with Fatima Maleki.

The new asking price will test how far apart buyers and sellers are in terms of price expectations in London’s luxury housing market. With high-end real estate under pressure from a triple whammy of economic uncertainty, higher rates and political turmoil, transactions across the capital’s most affluent postcodes fell by almost a quarter in September from the same month a year ago, according to data from researcher LonRes. That prompted the average sale price to drop 3.1% over the same period.

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The Malekis’ mansion, which was built in the early 1900s, has had only a handful of owners throughout its history, one of whom was acclaimed romance novelist Barbara Cartland. With a swimming pool, bar and reception areas equipped to accommodate over 100 guests, the property was well-suited to host a party last week where potential buyers were in attendance, according to the people.

Efforts to reach the family for comment were unsuccessful.

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The bleak outlook for high-end London real estate is partly down to a dearth of international buyers — historically among the keenest investors in elite properties — as well as the prospect of a less welcoming tax environment in the near future, according to LonRes. The UK’s Labour Party, which is leading the Conservatives by more than 20 percentage points in many national polls, wants to raise stamp duty for overseas buyers if they win the next general election, which could further weaken demand for luxury homes.

Additionally, high financing costs have led to a shift in mood.

“Buyers are refusing to view properties they feel are overpriced,” said Jo Eccles, managing director at buying agent Eccord. “Rather than chasing the market down with incremental discounts, we’ve seen sellers being much more decisive and opting for bold price reductions.”

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Still, the less debt-reliant nature of London’s luxury housing market means the costliest home transactions are proving more durable than cheaper ones.

Some 17% of ultra-high-net-worth individuals bought at least one home last year, according to a separate report from broker Knight Frank, and the wealthiest home owners are still securing deals. Indian billionaire Ravi Ruia, for instance, bought a £113 million London mansion overlooking Regent’s Park this summer.

The Malekis aren’t the only ones looking to offload high-end property in a tight market — Qatari Sheikh Hamad bin Jassim bin Jaber Al Thani is mulling the sale of two homes in London’s Knightsbridge and Belgravia districts — nor are they they alone in having to bring down their asking price. TV personality Simon Cowell recently sold his London home in Holland Park for £15 million — some £30 million below values reported in the press.

--With assistance from Liza Tetley.