Have you configure the Bright Box router wireless settings the same as the Sky wireless router settings as you say it worked successfully?
Have you used the Bright Box router (Intelligent wireless) to connect to the best available wireless channel? By default the router will automatically select the channel with the least interference in your area.
Setting the Wireless Channel or Extension Channel to 12 or 13 may sometimes cause compatibility issues with some wireless devices.
In desperation you could use the Sky wireless router as the wireless access point for your LAN wireless network.