My grandfather was a mark V tank driver, he joined up late in the war and luckily for him it was over as he finished his training. He died when I was only a year old so I never got a chance to talk to him sadly.
When I was at school in the I suppose you would call it the mechanics club they had a Rolls Royce engine from a Scorpion that I spent a summer of lunch breaks and more stripping cleaning reassembling and painting it's what got me into car mechanics
According to my dad my grandfather did say they had a habit of braking down! His was a male tank in about 1922 him and the rest of the crew won the army gunnery championship with the six pounder hotchkiss, basically a sawn off naval gun!