Educated at Eton and Trinity College Cambridge, Walter was commissioned into the Kent Yeomanry in 1934. He was promoted Lieutenant three years later. After war broke out he went with the regiment to France and then the Middle East where he served with distinction for which he was subsequently awarded a Military Cross.
His citation reveals that ”…In August and September 1942 he commanded a reformed battery when the Regiment was supporting 8th Armoured Brigade. A fierce battle ensued in which the calm and efficiency of this officer and his gallant leadership ensured his giving maximum support to the armour in what was a new type of warfare as far as the Regiment was concerned…."