One of the LRDG’s trucks, most probably  Nz T7 (“Te Hau”), a Chevrolet WA, and the gun is a 37mm Bofors. This vehicle took part in the attack on Murzuk on 11 January 1941. 

Heavy-armed truck

The cover of "Karys" ("Soldier") veakly magazine, that vas published for the soldiers of lithuanian army. After the 1991 these magazines are publicated once again. 
These magazines vere wery popular in intervar Lithuania, the covers usualy has some sort of military photography, in this case - infnatrymen with "Oerlicon" AA-AT canon

"Karys" magazine cover

Major Patrick  Andrew Clayton (DSO MBE), formerly a British Surveyor, was the Commander of the New Zealander’s “T” Patrol Unit  of the LRDG. In the picture, he is standing in front of the Chevrolet truck T2 “Te Taniwha”. Lybia, 1940. Major Clayton was hurt and captured by Italians of the Compagnia Sahariana at the ambush at Gebel Sheriff (January 31, 1941) and remained a POW in Italy until the Armistice on 8 September 1943. After being released, he remained free in Italy, until 9 January 1944, when he ended up in German captivity. He was liberated on 12 April 1945 by US advancing forces, while in a POW camp in Czechoslovakia. He died suddenly of a massive aneurism on 17 March 1962, at the age of 66.  