Hi, fellow Hartle here, also West Midlands, my father still going strong at 80 currently resides in East Sussex, although came from Birmingham. I have an older brother and sister and I personally have three sons, and my brother one, obviously all Hartles! So we seem to be going strong on male heirs here!
My father is one of twelve, most deceased now sadly although he has fond memeories of his youth.
We loked into the family tree many years ago, and had a 'cost of arms' plaque made, that showed a white hart and were informed that the name had great age, De Herthul was the first I heard. It is something I am keen to start looking into again, more so as I am now fifty and with my fathers great age I am keen to use what he can remember!