This is a novel about two people. The first is a British corporal who ends up commanding a Grant tank in North Africa. Stranded behind the lines, he and his crew have to attempt to break through to their own side. The second person is a German colonel, who is single-mindedly intent on bringing 40 Tiger tanks from Germany to aid Rommel. The two stories are interwoven. I found it a great read. Very well researched, and clearly focused on the horrors and waste of war.
I can't find any information about the author, other than he also wrote Fortress Eagle (Tank 2) and Sugar Sugar (Tank 3), both also published under the Corgi imprint in 1977 and 1978 respectively. I've got to keep my eye open for them.