Have a look at the Antarctic Strip Chart Appendix I in the Chippendale report.
If this is the same one to which you refer, there is a label for Beaufort Island, but the actual location (outline) of the island is not actually depicted on the chart.
I've never looked at chart aspect in detail so if they were given something better (like the USGS maps @ 1:250:000 of Ross Island and Franklin Island first published in 1962) please let me know.