CTG-10 Clip Tuner : Flakey device and inaccurate

Tried a few different things to get better results with this tuner at the end of my HB guitar but it still exhibits the following problems:

1. On "Guitar" mode, it struggles to find the right string to tune against, regularly bouncing around between notes and only rarely settling on the right note to measure against.

2. Sometimes the tuner fails to respond to any note and then becomes erratic.

3. Even when it finds the right note, the tuner struggles to hear the pitch being played, even in dead silent rooms. This leads to inaccurate readings, wildly erratic readings or no readings at all.

4. For example, starting with the bottom E string, the tuner sometimes thinks I'm playing A, D or even G strings!!

I've taken the (brand new) battery out and replaced it, cleaned the battery contacts and restarted the tuner multiple times but it makes no difference.

This tuner is a bit of a dud, I'm afraid.