Shift+key not working in 14.04.2 on pavilion 15 laptop

Recently installed Ubuntu 14.04.2 on HP Pavilion 15 laptop and found that when I select and hold Shift and then select certain keys (1,2,3,4) and or other keys (letters such as M) that nothing happens, no quote marks or pound sign etc.

I have found that if I quickly tap the shift key and follow it by the offending key (M or number 3) for example, that the symbol appears.

The keyboard is set to EN1 (English UK), the keyboard layout chart matches accordingly.
I've also tried using reconfig for the keyboard, I've changed the keyboard input methods to none and ibus to no avail.

Temporarily I'm using the sticky keys as a work around.

Have noticed when conducting search in google that many people have experienced similar issues.