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

When Yaz, Dan and Eustacius broke into the tomb where they discovered the pot, why and how were all the candles lit in the place?

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.