I see your problem. Apparently, if a person is still showing on the 1939 Register, it is probable that they are no longer on this earth. Obviously she married, as her surname now shows as Richards. You could try and trace her forward from this, starting around 1953-ish when she would have been 20. I suspect that the Register is actually showing the residents of a children's home as the previous records all show "This record is officially closed", indicating they are possibly all still living. However, why she should be in a children's home on the outskirts of Wakefield while her presumed parents are alive and living in Leeds is a mystery. There is a record of a Dorothy Hallas marrying John E Richards in 3Q1952 in Lower Agbrigg, which is a suburb of Wakefield. It might be worth sending for this marriage record which should give the father's/mother's name. I notice that there are a lot of Dorothy Hallases around on the BMDs and all in Yorkshire...could be tricky!
