four different charts
... that due of a lack of an official UK Singles Chart before 1969 the BBC averaged four different charts in the early 1960s, none of which are now regarded as the canonical source?
... that due of a lack of an official <a href="./UK_Singles_Chart" id="mwG3o" rel="mw:WikiLink" title="UK Singles Chart">UK Singles Chart</a> before 1969 the <a href="./BBC" id="mwG3s" rel="mw:WikiLink" title="BBC">BBC</a> averaged <b id="mwG3w"><a href="./List_of_UK_charts_and_number-one_singles_(1952–1969)" id="mwG30" rel="mw:WikiLink" title="List of UK charts and number-one singles (1952–1969)">four different charts</a></b> in the early 1960s, none of which are now regarded as the canonical source?