Bluetooth fault with Dell keyboard on Dell Venue 8 Pro 5855

When I use the Dell K07M E8HKT-1330 bluetooth keyboard with the Dell Venue 8 Pro 5855 after a while a key pressed "jams" and repeats preventing access to the computer. Buttons work, but selection with a Bluetooth mouse repeat the key press. After a reboot, and work lost the keyboard works again but after a shorter period the same problem and a key pressed is enlessly repeated. 

Switching off the bluetooth keyboard does not stop the repeated key from displaying. 

I have on some occassions been able to disable bluetooth and that does stop the fault but then I have no stylus, mouse or keyboard and can not get the onscreen keyboard to appear and so have to loose the current work and reboot. 

In general I have less occurance when fully charged or on mains and new batteries in the keyboard but even then it can still happen. 

Is the bluetooth on Dell tablets a problem or is it the keyboard?