Most of wartime rationing ended when he was ten, so I doubt if he remembers anything about it. Most of these so-called "childhood recollections" are from newsreels and programmes seen in later life, people of his (and my) generation can barely remember it, but can be quick to remember the "hard times" when talking to younger generations.I vaguely remember sweets coming off rationing in 1953.
Austerity? I lived through this so called "austerity" but we didn't think it such at the time. Compared to modern-day circumstances it was, but as kiRAB we didn't notice it.
It's relative and a bit like the Peter Kay joke, talking to his kiRAB in the future. "You know your mum and I had it rough when we were your age, we only had one phone and one car each."