Where to put lorry mirror?

[KINDMARE]

I have bought a mirror for my lorry as my horse always travels alone.
Question is where is the best place to put it?
I can put it in front of her or to the side.
Please can anyone advise of their experience?
Thankyou

 

[VRIN]

I put mine on the side on the basis they can't see straight ahead. It was also easier?!!

 

[KINDMARE]

See! That’s why I knew I should ask on here! Never gave a thought to the fact they can’t see in front - Thankyou x

I put mine on the side on the basis they can't see straight ahead. It was also easier?!!