My Smart Hub is Firmware version SG4B100021F4, last updated 22nd June 2016, and the option to rescan the wireless channels as shown in this BT Help article id not there.
I have loaded the Hub manager in Safari and Chrome on iOS and MacOS and the Rescan button does not appear on either platform or browser. Was this removed as a feature?
A few of us are almost human at the beginning of the day as well.
Dippu, for future reference, if you spot a mistake within an hour of hitting Post you can edit it from the Options list top right. Deleting the text completely may get the the resulting blank message removed in due course.