When Blackstone bought Chiswick Park for £480M in 2011, it seemed like a bit of an anomaly.

The U.S. private giant had been concentrating on central London, buying shiny assets like a stake in Broadgate or the Adelphi building from debt-laden sellers at rock bottom prices. The 1.9M SF west London business park was well-regarded, but hardly sexy.

Fast-forward nine years, and this week Blackstone completed the sale of the last building it still owned at Chiswick Park. In the process, it cemented a profit on its original deal that is likely to run to at least £450M.

In a moment that brings things full circle, Stanhope has bought the 334K SF, fully leased building seven at Chiswick Park for £312M. Stanhope developed Chiswick Park in the 1980s, and has bought the building, where tenants include Pernod Ricard, on behalf of unnamed investors.

Blackstone bought Chiswick Park from investors including Aberdeen, Schroders and Stanhope for £480M in 2011. It spent £70M developing a sixth building on the site in 2012 before selling the scheme to the China Investment Corporation for £780M in 2014.

The development site for building seven was not included in the deal. Blackstone spent £80M speculatively developing the building in 2013. Its total outlay on investment and development at Chiswick is roughly £630M, with the £1.1B recouped putting its profit at roughly £450M.

While it wasn’t considered the sexiest deal at the time, Chiswick Park has been a roaring success, maintaining near 100% occupancy.

Blackstone is also looking to offload another of its London office assets. It is looking to sell the 500K SF St Katherine Docks scheme on the eastern edge of the City for around £500M, according to React News. Blackstone bought the asset as part of its £450M takeover of Max Property in 2014. It has leased up and refinanced the asset and now is looking to sell.