Look for one thing - Find another.
As far as I can see - by the indistinct number - she is Hall Class Collet, Dorford Hall, at that time, running under British Rail and was decommissioned in January 1965. This picture was taken around 1962 or 3. I can't be certain but it look as though she was running a mail train? That is going by the unusual carriages just behind the loco.
I wonder what she would be worth today as a running loco? even as dirty and scruffy looking as she is in this picture?