One of the main reasons it chose to upgrade was the tighter integration the Windows Phone devices offered with Foxtons' existing Microsoft email client Outlook.
The other advantage Nokia mentions are the Office applications bundled with the device — a key differentiator for it as an enterprise device compared to the iPhone, which Office does not support yet.
Nokia is also touting benefits of the Windows Phone platform for developers familiar with building for Windows, pointing to a personnel management app Foxtons is building.
"In a fast-moving business with many staff movements across departments and locations, keeping an accurate, up-to-date contact list is a challenge for us," said Foxtons' director of IT, Dan Rafferty, in a statement.
"We've developed an app integrating our personnel system with our active directory and phone system so all the information is accurate and can be accessed directly from our agents' Nokia Lumia 820s. It's a great timesaver and asset for the team. The Nokia Lumia 820 aligns with our entire device strategy and allows us to fully integrate our current Microsoft systems throughout the company."
Nokia announced better-than-expected Lumia sales in the fourth quarter of 2012 and even stronger sales of its low-end Asha line, but as analyst firm Gartner noted recently, these have not been large enough to offset lost market share from the decline in sales of its abandoned Symbian platform.