Story as told to me...I wonder if there is truth in it?

In the late 70's someone I knew related a story to me about his time in the British army. Listening to him at the time I could only think 'this sounds like and should be made into a film'.

Doug would have been about 70 in 1976. I was aware that he was an old soldier who had served in Malaya against the communist insurgents. For me though, of greater interest, was his tale of being part of a secret British Engineer unit sent from India to help the Cheng Kai Shek Nationalists in China in the late 30's. 

Doug and his group of about 20 soldiers were sent in to help the nationalists against the communists even though the country had been invaded by the Japanese at the same time. From his reports they were moving cross country helping repair or blow up bridges / infrastructure. One of things Doug also said was how corrupt the local leaders of the troops  could be. Apparently they often bartered with the enemy as to whether bridges would be destroyed or left in tact. 

A big surprise was revealed by Doug when one morning the British unit woke up to find themselves under arrest by the Chinese troops they had been escorting and helping. In the following weeks they were led as prisoners cross country by their captors. Doug related how the conditions they were living in were very poor, a lack of food, illness and terrible weather causing the deaths of several in the group. With this hopeless situation in play Doug's commander decided to lead an escape of ten men away from the nationalist Chinese who had betrayed them. Apparently the escape was easier than they could have hoped but it was into a hellish situation where they were wandering in unknown surroundings with three potential enemy groups all likely to kill them. 

Doug told of a difficult journey made even more difficult by the fact that the groups commander actually went temporarily insane there and then! In response the groups survivors resolved to carry their commander with them rather than leave him behind. They literally tied him to a stretcher screaming and shouting before gagging him in case he gave away their presence. Weeks went by and the group made their way towards the Burmese border and a hope they might run into friendly troops and be saved. In the event this rag tag bunch were intercepted and arrested! Almost unrecognisable as troops they were taken as prisoners to India ironically to the city where they had originally set out. There they stayed for a month in prison unrecognised having been originally dispatched in secret to China. 

Then, out of the blue, an officer involved in the original dispatch from India returned to the Indian base and identified this bedraggled group as British troops. 

As fantastic as the story sounds Doug had one more twist to his tale to report. The commander, who had suffered temporary insanity and been carried kicking and screaming for hundreds of miles by his loyal troops, was awarded a significant medal for his success in bringing out and saving the group!

Well that is the story as related to me. It sounds like a Hollywood movie script. If anyone can give some background / confirmation to all this I would appreciate it😊.