Any info gratefully received

Hello.
Whilst looking through some of my Grandfather's belongings lately I came across an old photograph; it is of Mongomery standing on the bonnet of a jeep making a speech.
On the back is written (in Polish) 'BAOR Mongomery speech to Poles'.
I've decided to look into this further and so far have discovered this page.
All I know about my Grandfather's time in the war is that his village was invaded by the Russians, he was due to be taken to Siberia but escaped, he then got caught by the Germans and was put in a prisoner of war camp in Norway, from which he also escaped. He eventually ended up as prison of war camp guard in Scotland and later in Derbyshire. I've no idea what he did in the intervening years and had no idea of this 'BAOR'.
I'd like to find out more and if anyone could point me in the right direction I'd be most grateful.
Thanks,
Phil.