Bundjuwanga appears to be a dialect of Nyamal A58 or another name for Nyamal. Oates (1975:74) says that it was studied and termed by von Brandenstein as 'heavy' Njamal A58.
Documentation for Nyamal A58 may be relevant.
Area encompassing headwaters of Turner, Shaw and Coongan Rivers, Studied by von Brandenstein who termed it 'heavy' Njamal (Oates 1975:74). Njamal also inhabit the headwaters of the Yule and Turner rivers east of Wodjina. They are the ['Pundju ] or 'heavy' speakers of Njamal (Tindale 1974).
Speaker numbers were measured differently across the censuses and various other sources listed in AUSTLANG. You are encouraged to refer to the sources.
Speaker numbers for ‘NILS 2004’ and ‘2005 estimate’ come from 'Table F.3: Numbers of speakers of Australian Indigenous languages (various surveys)' in 'Appendix F NILS endangerment and absolute number results' in McConvell, Marmion and McNicol 2005, pages 198-230 (PDF, 2.5MB).