Depending on what you've got Settings > General > Use Side Switch To set to (mute or rotation lock), then one function is controlled via the switch on the right hand side of the iPad above the volume switch and the other function is controlled via the left-hand end of the taskbar : double-click the home button; slide from the left; and it's the icon far left; press home again to exit the taskbar. The function that isn't on the side switch is set via the taskbar instead : http://support.apple.com/kb/HT4085
So if the side switch is controlling roation lock, then open the taskbar at the bottom of the screen and swipe it to the right, and the icon far left is for muting/unmuting notifications.
Hi King Penguin
Many thanks for your prompt reply. I have just discovered a small lock button above the volume button on the right hand side in portrait. I have to say I hadn't.noticed this button until now. I did follow the logics of one function being controlled by the switch and the other being controlled by the icon on the tasking bar. However, if, like me and you,re a complete pudding and have inadvertently activated this little locks button, then whatever function you assign to the button will not work.
Got it sorted now, so thanks very much, feel better knowing you,re lurking!
Kind regards and happy new year...whilst walking on the beach yesterday in Northumberland, I have to say I didn't,t spot a single King Penguin