[NTG-context] Appendix question

A (hopefully) simple question this time: Why would my appendices be labelled as Appendix One, Appendix Two etc., instead of Appendix A, Appendix B? I thought Appendices would normally be labelled alphabetically, not numerically. So I get APPENDIX as the label, I have: \setuplabeltext   [en]   [chapter={\bf Chapter }, appendix=APPENDIX ] But elsewhere I have: \setupheads[chapter][indentnext=no,conversion=Words,distance=.25em] So is that what is affecting my appendices, and if so how do I do it so that Chapters get words (One, Two, etc) and Appendices get letters (A,B, etc)? Julian