Theory:Doctor Who television discontinuity and plot holes/Survivors of the Flux

There is something of a contradiction here. In the story, Lethbridge-Stewart is refered to a corporal in 1967, which does not fit with him being a Colonel in that same year (The Web of Fear) neither would it be possible to rise in rank from Corporal - a junior non-commissioned officer - to Brigadier - a very senior army officer in just few short years. Also, it is very unlikely that an enlisted man - even if he gained a field commission - would ever rise to such a high rank in the British Army; without having attended the academy at Sandhurst.