My 13 year old son went to see it with a friend of mine earlier this week and I think they were both surprised about how much they loved it:-

Michael Morpurgo, the acclaimed children’s author of over 100 books (including Warhorse) wrote this multi-award winning story of enduring friendship. It contains all the typical characteristics of a Michael Morpurgo classic – animals, the First World War, the power of storytelling and overt sentimentality. The play tell as a lovely lifetime story between a young boy and his special white lion friend. When young Michael runs away from his boarding school, he finds temporary refuge with the elderly Millie in an old house nearby. She tells him the story of another runaway, the first-world-war hero Bertie, who turned up at her house when she was just a girl after escaping from the same school. Bertie grew up in South Africa, where he saved an orphaned white lion cub from being savaged by hyenas. But when he was sent to school in England, the tame lion was sold to a French circus owner; Both boy and cub miss the bond which has grown between them and Bertie vows that he and the lion will one day be reunited. Little does he know the adventurous, romantic, shocking turns his life will take before that day finally comes.
My friend says “this is an ideal show for all the family, both children and adults, with a lovely musick (she’s Polish), special light effects and excitement for what is going to happen next. We both liked the play very much and having seen it, we felt even more happy then we were before. I think I might even watch it again because I loved it!!
My son added to this by saying “I really enjoyed the play and think it would be perfect for a family as it is funny, moving and exciting. I loved it and can’t give any further improvements to what has already been said about it” (he’s lazy).