It was Forum Press who, in one of their brief short stories, after the Master Detective full story in August 2001, advised incorrectly the date of the death of Robinson. This is what was confusing people. You are quite correct that the story in MD 2020 is is a reprint of your 2001 story apart from the last couple of paragraphs.
Forum Press might have made a slight error, but it was nothing compared to the one below:
Excerpt taken from Newcastle Journal (Thursday 27th January 1977) "So after getting 'Life' for the first murder John George Robinson was paroled 14 years later and he killed again. The Judge at the original murder trial, in 1962, Mr Justice Finnemore recommended in open court that Robinson should never be released from prison. But he did not put his feelings in writing to the Home Secretary, the normal custom in such cases, and the parole board had no formal knowledge of the recommendation. Transcripts of the case and their accompanying shorthand notes were destroyed, as Robinson (47) of Spennymoor, Co Durham, did not appeal against his sentence or conviction. And ironically, both the Judge and the shorthand writer, who may have been able to provide vital information for the board have since died...... ....A Home Office spokesman said it was extremely unlikely the reasons for the parole would be made public"
Makes you think what other "vital information" did the parole board need to know, other than he cold-bloodedly killed a small boy?