grass is not supposed to be 1inch long - it grows becuase its supposed to be that way, long and wavy.
you may be surprised to hear that many people want their gardens to actually look like a garden and not like a green carpet
it is their garden, they can have it the way they want - what on earth makes you think other people have to adhere to your idea of what a garden should look like?
i cannot believe you had the nerve to approach the letting agent, with this petty nonsense!
although, you could always mow it yourself....