Wireless Keyboard Issues - Backspace not behaving

this is driving me insane.

Ive spent hoours lookign for a solution and it's making it almost impossible to get on with any work.

Everything was fine, never had any problems.

then I changed the batteries on the keyboard. I think i went from one set of recharageables to another.

the biggest frustration is the behaviour of the backspace key, which does nopt backspace and delete as it should.

It now deletes to the left!

Also the arrows do not behave as they used to do and I'm unable to type a capital t.

I've tried everything, i.e. turnign it on and off, re-pairing, going through the keyboard settings, resoring everything to default etc etc

Keyboard operation reverts to normal operation if I turn it off and on , but only for a few minutes.

I thoughth it might be something to do with the rechargeable batteries, so replaced them with alkaline. - no effect.

HELP!!

the only clue that something might be wrong is, when Ive done some kind of keyboard key test where you are shown a layoput of the keyboard and it highlights the key you are pressing. he keyboard map shows the arrow on the backspace key to be facing in the opposite way to the way it actually is!

Also Ive noticed the bluetooth symbol at the top of the screen has the 3 dots horizontal - which i thought indicated low battery, but the battery is fine as Ive just replaced them.