From email to BBC Trust, 15 March 2017:

"Trustees' text as a whole misleads.  In reality, Trustees have no evidence to support the impression they give, that somehow the BBC's errors are less serious because there was a "commitment" in 2001 to 1990-2015 targets.

1.  It was not the "UN", in the sense of member states, who published the easier targets in a "road map".  It was the Secretary-General, merely making proposals.  The United Nations General Assembly responded on 14 December 2001 by asking UN staff to publicise the actual 15-year commitments:  "widespread publicity to the Millennium Declaration and to increase the dissemination of information on the Declaration".
https://documents-dds-ny.un.org/doc/UNDOC/GEN/N01/479/63/DOC/N0147963.DOC

2.  The mention of one target understates the complaint. It was not only the target for "under-five child mortality" which was more ambitious in the actual pledges by world leaders than the BBC has give the public to believe.  The BBC has basically failed to report the actual 15-year commitments even after complaints.  In those complaints is ample evidence that the BBC has in effect understated the pledges on poverty, hunger, maternal mortality, and water.  

3.  There was no "commitment" in 2001 by member states to the easier 1990 baseline (see link above).  

4.  Even if Trustees had been right that there was such a "commitment", it would still be true that BBC output has been highly misleading over many years, in a way damaging to the democratic process.  The BBC has persistently given a wrong impression that the agreement of 2000 had a 25-year time frame.  
Even if Trustees had been correct that there was a "commitment" in 2001 to a 25-year timeframe, it would not excuse the BBC's failures to report, or its wrong reporting. This is because the actual 15-year pledges were never rescinded. A commitment is not removed by a lesser commitment.  
Even more difficult for the BBC position is this:  Right up until 2015, nations specifically recommitted to the 15-year pledges.  For example: "The EU and its Member States remain strongly committed to the Millennium Declaration" (Delegation of the European Union to the UN, 8 January 2015, http://eu-un.europa.eu/articles/en/article_15930_en.htm).  After 2001 member states kept reaffirming previous commitments, which included the more ambitious pledge by the 1996 World Food Summit.

Had the Trustees given a proper account of the basic facts, their response to this and subsequent appeals, and BBC output at the time of the 2015 Summit, might have been significanly different."