Harriet Harman: the unanswered question

In the BBC coverage of this story and Harriet Harman's online statement I can see no mention of this point: In a letter to the Home Office in April 1978, the NCCL argued that child pornography should not be banned as “indecent” unless it could be shown that the child depicted had been harmed. The NCCL official who wrote this letter was its legal officer, Harriet Harman.

Am I correct, did she sign that letter? Why?