Warning from telecoms watchdog comes as it releases new app that allows people to test their Wi-Fi set up. Wireless broadband may not be working as well as it could in nearly six million UK homes and offices, according to research published by UK regulator Ofcom, and it’s often down to the way the Wi-Fi is set up. In a press release, Ofcom said: “It could be down to something as simple as interference from other electronic devices, such as…